全文获取类型
收费全文 | 2420篇 |
免费 | 76篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 17篇 |
化学工业 | 464篇 |
金属工艺 | 38篇 |
机械仪表 | 83篇 |
建筑科学 | 69篇 |
矿业工程 | 2篇 |
能源动力 | 58篇 |
轻工业 | 194篇 |
水利工程 | 23篇 |
石油天然气 | 4篇 |
无线电 | 218篇 |
一般工业技术 | 403篇 |
冶金工业 | 557篇 |
原子能技术 | 38篇 |
自动化技术 | 329篇 |
出版年
2023年 | 22篇 |
2022年 | 74篇 |
2021年 | 101篇 |
2020年 | 43篇 |
2019年 | 64篇 |
2018年 | 60篇 |
2017年 | 57篇 |
2016年 | 73篇 |
2015年 | 35篇 |
2014年 | 85篇 |
2013年 | 139篇 |
2012年 | 107篇 |
2011年 | 144篇 |
2010年 | 96篇 |
2009年 | 113篇 |
2008年 | 96篇 |
2007年 | 80篇 |
2006年 | 60篇 |
2005年 | 60篇 |
2004年 | 41篇 |
2003年 | 50篇 |
2002年 | 42篇 |
2001年 | 27篇 |
2000年 | 34篇 |
1999年 | 38篇 |
1998年 | 198篇 |
1997年 | 120篇 |
1996年 | 93篇 |
1995年 | 40篇 |
1994年 | 49篇 |
1993年 | 48篇 |
1992年 | 19篇 |
1991年 | 12篇 |
1990年 | 8篇 |
1989年 | 22篇 |
1988年 | 13篇 |
1987年 | 8篇 |
1986年 | 12篇 |
1985年 | 15篇 |
1984年 | 5篇 |
1983年 | 10篇 |
1982年 | 9篇 |
1981年 | 12篇 |
1980年 | 6篇 |
1979年 | 4篇 |
1977年 | 7篇 |
1976年 | 15篇 |
1974年 | 4篇 |
1969年 | 3篇 |
1967年 | 7篇 |
排序方式: 共有2497条查询结果,搜索用时 15 毫秒
101.
Claudia Giuseppina Fresta Giuseppe Caruso Annamaria Fidilio Chiara Bianca Maria Platania Nicol Musso Filippo Caraci Filippo Drago Claudio Bucolo 《International journal of molecular sciences》2020,21(23)
Activation of P2X7 signaling, due to high glucose levels, leads to blood retinal barrier (BRB) breakdown, which is a hallmark of diabetic retinopathy (DR). Furthermore, several studies report that high glucose (HG) conditions and the related activation of the P2X7 receptor (P2X7R) lead to the over-expression of pro-inflammatory markers. In order to identify novel P2X7R antagonists, we carried out virtual screening on a focused compound dataset, including indole derivatives and natural compounds such as caffeic acid phenethyl ester derivatives, flavonoids, and diterpenoids. Molecular Mechanics/Generalized Born Surface Area (MM/GBSA) rescoring and structural fingerprint clustering of docking poses from virtual screening highlighted that the diterpenoid dihydrotanshinone (DHTS) clustered with the well-known P2X7R antagonist JNJ47965567. A human-based in vitro BRB model made of retinal pericytes, astrocytes, and endothelial cells was used to assess the potential protective effect of DHTS against HG and 2′(3′)-O-(4-Benzoylbenzoyl)adenosine-5′-triphosphate (BzATP), a P2X7R agonist, insult. We found that HG/BzATP exposure generated BRB breakdown by enhancing barrier permeability (trans-endothelial electrical resistance (TEER)) and reducing the levels of ZO-1 and VE-cadherin junction proteins as well as of the Cx-43 mRNA expression levels. Furthermore, HG levels and P2X7R agonist treatment led to increased expression of pro-inflammatory mediators (TLR-4, IL-1β, IL-6, TNF-α, and IL-8) and other molecular markers (P2X7R, VEGF-A, and ICAM-1), along with enhanced production of reactive oxygen species. Treatment with DHTS preserved the BRB integrity from HG/BzATP damage. The protective effects of DHTS were also compared to the validated P2X7R antagonist, JNJ47965567. In conclusion, we provided new findings pointing out the therapeutic potential of DHTS, which is an inhibitor of P2X7R, in terms of preventing and/or counteracting the BRB dysfunctions elicited by HG conditions. 相似文献
102.
Rossi EA Vendramini RC Carlos IZ de Oliveira MG de Valdez GF 《Archivos latinoamericanos de nutrición》2003,53(1):47-51
This study was undertaken to verify the effect of a daily intake of a new fermented soy milk produced with Enterococcus faecium and Lactobacillus jugurti on the serum lipid levels in normocholesterolemic middle-aged men. The study was randomized, double-blind and placebo-controlled and was performed for a period of 6 weeks. Forty-four normocholesterolemic healthy, male volunteers, aged 40-55 years old were randomly separated in two groups: The F-group received 200 ml of the fermented product daily and the P-group received 200 ml of placebo (chemically fermented). The blood samples were drawn initially and after 3 and 6 weeks and serum values for total cholesterol, HDL-cholesterol and triglyceride were determined. The LDL-cholesterol value was estimated. No significant changes in the fermented group (F) were observed for total cholesterol, LDL-cholesterol or triglyceride levels, while the HDL-cholesterol level was significantly higher (p < or = 0.05) after 6 weeks. The total cholesterol and LDL-cholesterol levels were significantly higher (p < or = 0.05) in the placebo group (P), but no changes were found for the HDL-cholesterol and triglyceride levels during the experimental period. In conclusion, the intake of 200 ml/day of the fermented soy milk, produced with E. faecium and L. jugurti, for 6 weeks, did not affect the serum total cholesterol and LDL-cholesterol, and led an increase of 10% in the HDL-cholesterol level. 相似文献
103.
Gianmaria Salvio Alessandro Ciarloni Melissa Cutini Nicola delli Muti Federica Finocchi Michele Perrone Silvia Rossi Giancarlo Balercia 《International journal of molecular sciences》2022,23(10)
Metabolic syndrome (MetS) is a highly prevalent condition among adult males, affecting up to 41% of men in Europe. It is characterized by the association of obesity, hypertension, and atherogenic dyslipidemia, which lead to premature morbidity and mortality due to cardiovascular disease (CVD). Male infertility is another common condition which accounts for about 50% of cases of couple infertility worldwide. Interestingly, male infertility and MetS shares several risk factors (e.g., smoking, ageing, physical inactivity, and excessive alcohol consumption), leading to reactive oxygen species (ROS) production and increased oxidative stress (OS), and resulting in endothelial dysfunction and altered semen quality. Thus, the present narrative review aims to discuss the pathophysiological mechanisms which link male infertility and MetS and to investigate the latest available evidence on the reproductive consequences of MetS. 相似文献
104.
Lara Alessandrini Leonardo Franz Marta Sbaraglia Tommaso Saccardo Filippo Cappello Alessandro Drigo Anna Chiara Frigo Gino Marioni 《International journal of molecular sciences》2022,23(14)
Programmed cell death ligand 1 (PD-L1) seems to rely on close relations between neoplastic and immune cells in the tumor microenvironment. Tumor to stroma ratio (TSR) has been associated with prognosis in different malignancies. The aims of this exploratory investigation were to analyze for the first time the: (i) association between TSR, PD-L1 expression and other clinical–pathological features in laryngeal squamous cell carcinoma (LSCC) biopsies and paired surgical specimens; (ii) prognostic and predictive role of TSR and PD-L1. TSR, PD-L1 expression (in terms of combined positive score [CPS]), and other clinical–pathological features were analyzed in biopsies and surgical specimens of 43 consecutive LSCC cases. A CPS < 1 evaluated on surgical specimens was associated with a low TSR (stroma rich) on both biopsies and surgical specimens (p = 0.0143 and p = 0.0063). Low TSR showed a significant negative prognostic value when evaluated on both biopsies and surgical specimens (HR = 8.808, p = 0.0003 and HR = 11.207, p = 0.0002). CPS ≥ 1 appeared to be a favorable prognostic factor (HR = 0.100, p = 0.0265). The association between bioptic and surgical specimen TSR and PD-L1 expression should be further investigated for a potential impact on targeted treatments, also with regard to immunotherapeutic protocols. 相似文献
105.
Molecular Framework of Mouse Endothelial Cell Dysfunction during Inflammation: A Proteomics Approach
Michael T. Rossi Jordan C. Langston Narender Singh Carmen Merali Qingliang Yang Salim Merali Balabhaskar Prabhakarpandian Laurie E. Kilpatrick Mohammad F. Kiani 《International journal of molecular sciences》2022,23(15)
A key aspect of cytokine-induced changes as observed in sepsis is the dysregulated activation of endothelial cells (ECs), initiating a cascade of inflammatory signaling leading to leukocyte adhesion/migration and organ damage. The therapeutic targeting of ECs has been hampered by concerns regarding organ-specific EC heterogeneity and their response to inflammation. Using in vitro and in silico analysis, we present a comprehensive analysis of the proteomic changes in mouse lung, liver and kidney ECs following exposure to a clinically relevant cocktail of proinflammatory cytokines. Mouse lung, liver and kidney ECs were incubated with TNF-α/IL-1β/IFN-γ for 4 or 24 h to model the cytokine-induced changes. Quantitative label-free global proteomics and bioinformatic analysis performed on the ECs provide a molecular framework for the EC response to inflammatory stimuli over time and organ-specific differences. Gene Ontology and PANTHER analysis suggest why some organs are more susceptible to inflammation early on, and show that, as inflammation progresses, some protein expression patterns become more uniform while additional organ-specific proteins are expressed. These findings provide an in-depth understanding of the molecular changes involved in the EC response to inflammation and can support the development of drugs targeting ECs within different organs. Data are available via ProteomeXchange (identifier PXD031804). 相似文献
106.
Vanessa Modelski Schatkoski Thaís Larissa do Amaral Montanheiro Beatriz Rossi Canuto de Menezes Raissa Monteiro Pereira Karla Faquine Rodrigues Renata Guimarães Ribas Diego Morais da Silva Gilmar Patrocínio Thim 《Ceramics International》2021,47(3):2999-3012
Studies related to biomaterials that stimulate the repair of living tissue have increased considerably, improving the quality of many people's lives that require surgery due to traumatic accidents, bone diseases, bone defects, and reconstructions. Among these biomaterials, bioceramics and bioactive glasses (BGs) have proved to be suitable for coating materials, cement, scaffolds, and nanoparticles, once they present good biocompatibility and degradability, able to generate osteoconduction on the surrounding tissue. However, the role of biomaterials in hard tissue engineering is not restricted to a structural replacement or for guiding tissue regeneration. Nowadays, it is expected that biomaterials develop a multifunctional role when implanted, orchestrating the process of tissue regeneration and providing to the body the capacity to heal itself. In this way, the incorporation of specific metal ions in bioceramics and BGs structure, including magnesium, silver, strontium, lithium, copper, iron, zinc, cobalt, and manganese are currently receiving enhanced interest as biomaterials for biomedical applications. When an ion is incorporated into the bioceramic structure, a new category of material is created, which has several unique properties that overcome the disadvantages of primitive material and favors its use in different biomedical applications. The doping can enhance handling properties, angiogenic and osteogenic performance, and antimicrobial activity. Therefore, this review aims to summarize the effect of selected metal ion dopants into bioceramics and silicate-based BGs in bone tissue engineering. Furthermore, new applications for doped bioceramics and BGs are highlighted, including cancer treatment and drug delivery. 相似文献
107.
Marco Bocchetti Maria Grazia Ferraro Filippo Ricciardiello Alessandro Ottaiano Amalia Luce Alessia Maria Cossu Marianna Scrima Wing-Yan Leung Marianna Abate Paola Stiuso Michele Caraglia Silvia Zappavigna Tung On Yau 《International journal of molecular sciences》2021,22(8)
Colorectal cancer (CRC) is the third most deadly cancer worldwide, and inflammatory bowel disease (IBD) is one of the critical factors in CRC carcinogenesis. IBD is responsible for an unphysiological and sustained chronic inflammation environment favoring the transformation. MicroRNAs (miRNAs) belong to a class of highly conserved short single-stranded segments (18–25 nucleotides) non-coding RNA and have been extensively discussed in both CRC and IBD. However, the role of miRNAs in the development of colitis-associated CRC (CAC) is less clear. The aim of this review is to summarize the major upregulated (miR-18a, miR-19a, miR-21, miR-31, miR-155 and miR-214) and downregulated (miR-124, miR-193a-3p and miR-139-5p) miRNAs in CAC, and their roles in genes’ expression modulation in chronic colonic-inflammation-induced carcinogenesis, including programmed cell-death pathways. These miRNAs dysregulation could be applied for early CAC diagnosis, to predict therapy efficacy and for precision treatment. 相似文献
108.
In this study we conducted a survey of the concentrations of the major 1,2-dicarbonyl compounds in 40 commercial honey samples from 12 different floral origins. 3-Deoxyglucosone (3-DG), glyoxal (GO), and methylglyoxal (MGO) were measured, using their corresponding quinoxaline derivatives, by high-performance liquid chromatography (HPLC). The analytical performance of the HPLC method for the analysis of 1,2-dicarbonyl compounds was evaluated in terms of linearity, limits of detection (LODs), limits of quantification (LOQs), and precision. Linearity over 2 orders of magnitude, LODs (0.01-0.04 mg/kg), and LOQs (0.03-0.12 mg/kg) were calculated. Instrumental precision, as measured by the repeatability relative standard deviation% (RSDr%), was found to be between 0.22% and 0.55%. Furthermore, the concentrations of factors GO and MGO with respect to 3-DG were also calculated for rapid quantification in honey. In honey samples, the concentrations of 3-DG ranged from 75.9 to 808.6 mg/kg and were significantly higher (up to 100-fold) than those of 5-hydroxymethylfurfural (HMF). Values for GO and MGO were 0.1-10.9 and 0.2-2.9 mg/kg, respectively. The chemical characteristics that most influenced the levels of 1,2-dicarbonyl compounds in honey were found to be pH and total phenols. This was supported by multivariate analysis used to classify different honey types with respect to their chemical characteristics. In addition, both dicarbonyls and phenols are believed to contribute to the development of the final color of honey. 相似文献
109.
Kuwanon‐L as a New Allosteric HIV‐1 Integrase Inhibitor: Molecular Modeling and Biological Evaluation 下载免费PDF全文
Dr. Francesca Esposito Dr. Cristina Tintori Dr. Riccardo Martini Dr. Frauke Christ Prof. Zeger Debyser Roberto Ferrarese Dr. Gianluigi Cabiddu Dr. Angela Corona Dr. Elisa Rita Ceresola Dr. Andrea Calcaterra Dr. Valentina Iovine Prof. Bruno Botta Dr. Massimo Clementi Dr. Filippo Canducci Prof. Maurizio Botta Prof. Enzo Tramontano 《Chembiochem : a European journal of chemical biology》2015,16(17):2507-2512
HIV‐1 integrase (IN) active site inhibitors are the latest class of drugs approved for HIV treatment. The selection of IN strand‐transfer drug‐resistant HIV strains in patients supports the development of new agents that are active as allosteric IN inhibitors. Here, a docking‐based virtual screening has been applied to a small library of natural ligands to identify new allosteric IN inhibitors that target the sucrose binding pocket. From theoretical studies, kuwanon‐L emerged as the most promising binder and was thus selected for biological studies. Biochemical studies showed that kuwanon‐L is able to inhibit the HIV‐1 IN catalytic activity in the absence and in the presence of LEDGF/p75 protein, the IN dimerization, and the IN/LEDGF binding. Kuwanon‐L also inhibited HIV‐1 replication in cell cultures. Overall, docking and biochemical results suggest that kuwanon‐L binds to an allosteric binding pocket and can be considered an attractive lead for the development of new allosteric IN antiviral agents. 相似文献
110.
Filippo Lococo Massimiliano Paci Cristian Rapicetta Teresa Rossi Valentina Sancisi Luca Braglia Silvio Cavuto Alessandra Bisagni Italia Bongarzone Douglas M. Noonan Adriana Albini Sally Maramotti 《International journal of molecular sciences》2015,16(8):19612-19630
Assessment of biological diagnostic factors providing clinically-relevant information to guide physician decision-making are still needed for diseases with poor outcomes, such as non-small cell lung cancer (NSCLC). Epidermal growth factor receptor (EGFR) is a promising molecule in the clinical management of NSCLC. While the EGFR transmembrane form has been extensively investigated in large clinical trials, the soluble, circulating EGFR isoform (sEGFR), which may have a potential clinical use, has rarely been considered. This study investigates the use of sEGFR as a potential diagnostic biomarker for NSCLC and also characterizes the biological function of sEGFR to clarify the molecular mechanisms involved in the course of action of this protein. Plasma sEGFR levels from a heterogeneous cohort of 37 non-advanced NSCLC patients and 54 healthy subjects were analyzed by using an enzyme-linked immunosorbent assay. The biological function of sEGFR was analyzed in vitro using NSCLC cell lines, investigating effects on cell proliferation and migration. We found that plasma sEGFR was significantly decreased in the NSCLC patient group as compared to the control group (median value: 48.6 vs. 55.6 ng/mL respectively; p = 0.0002). Moreover, we demonstrated that sEGFR inhibits growth and migration of NSCLC cells in vitro through molecular mechanisms that included perturbation of EGF/EGFR cell signaling and holoreceptor internalization. These data show that sEGFR is a potential circulating biomarker with a physiological protective role, providing a first approach to the functional role of the soluble isoform of EGFR. However, the impact of these data on daily clinical practice needs to be further investigated in larger prospective studies. 相似文献