全文获取类型
收费全文 | 2923篇 |
免费 | 109篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 27篇 |
综合类 | 1篇 |
化学工业 | 691篇 |
金属工艺 | 39篇 |
机械仪表 | 92篇 |
建筑科学 | 93篇 |
矿业工程 | 2篇 |
能源动力 | 79篇 |
轻工业 | 274篇 |
水利工程 | 26篇 |
石油天然气 | 5篇 |
无线电 | 248篇 |
一般工业技术 | 457篇 |
冶金工业 | 563篇 |
原子能技术 | 41篇 |
自动化技术 | 397篇 |
出版年
2024年 | 5篇 |
2023年 | 30篇 |
2022年 | 89篇 |
2021年 | 104篇 |
2020年 | 49篇 |
2019年 | 48篇 |
2018年 | 60篇 |
2017年 | 72篇 |
2016年 | 93篇 |
2015年 | 56篇 |
2014年 | 82篇 |
2013年 | 175篇 |
2012年 | 143篇 |
2011年 | 203篇 |
2010年 | 132篇 |
2009年 | 159篇 |
2008年 | 132篇 |
2007年 | 112篇 |
2006年 | 81篇 |
2005年 | 84篇 |
2004年 | 67篇 |
2003年 | 74篇 |
2002年 | 66篇 |
2001年 | 37篇 |
2000年 | 38篇 |
1999年 | 45篇 |
1998年 | 203篇 |
1997年 | 116篇 |
1996年 | 97篇 |
1995年 | 51篇 |
1994年 | 47篇 |
1993年 | 45篇 |
1992年 | 23篇 |
1991年 | 17篇 |
1990年 | 12篇 |
1989年 | 25篇 |
1988年 | 14篇 |
1987年 | 7篇 |
1986年 | 13篇 |
1985年 | 23篇 |
1984年 | 7篇 |
1983年 | 10篇 |
1982年 | 10篇 |
1981年 | 14篇 |
1980年 | 4篇 |
1979年 | 4篇 |
1978年 | 4篇 |
1977年 | 8篇 |
1976年 | 15篇 |
1967年 | 7篇 |
排序方式: 共有3035条查询结果,搜索用时 15 毫秒
81.
Umberto De Rossi Johannes Moll Monika Spieles Günther Bach Siegfried Dhne Jrg Kriwanek Maria Lisk 《Advanced Synthesis \u0026amp; Catalysis》1995,337(1):203-208
Cyanine dyes ( 1a–d ) with the 5,5′,6,6′-tetrachloro-1,1′-dialkyl-3,3′-di-(3-carboxypropyl)-benzimidocarbocyanine chromophore differing only in the chain length of their alkyl groups in 1,1′-position have been synthesized, spectroscopically characterized, and compared with 5,5′6,6′-tetrachloro-1,1′-diethyl-3,3′-di-(4-sulfobutyl)-benzimidocarbocyanine( TDBC ). In aqueous solution the dyes form J-aggregates which, depending on the alkyl group chain length, exhibit J-bands differing in spectral positions, bandwidth, and in the number of peaks. 相似文献
82.
Parastoo Memarian Elham Pishavar Federica Zanotti Martina Trentini Francesca Camponogara Elisa Soliani Paolo Gargiulo Maurizio Isola Barbara Zavan 《International journal of molecular sciences》2022,23(3)
The successful clinical application of bone tissue engineering requires customized implants based on the receiver’s bone anatomy and defect characteristics. Three-dimensional (3D) printing in small animal orthopedics has recently emerged as a valuable approach in fabricating individualized implants for receiver-specific needs. In veterinary medicine, because of the wide range of dimensions and anatomical variances, receiver-specific diagnosis and therapy are even more critical. The ability to generate 3D anatomical models and customize orthopedic instruments, implants, and scaffolds are advantages of 3D printing in small animal orthopedics. Furthermore, this technology provides veterinary medicine with a powerful tool that improves performance, precision, and cost-effectiveness. Nonetheless, the individualized 3D-printed implants have benefited several complex orthopedic procedures in small animals, including joint replacement surgeries, critical size bone defects, tibial tuberosity advancement, patellar groove replacement, limb-sparing surgeries, and other complex orthopedic procedures. The main purpose of this review is to discuss the application of 3D printing in small animal orthopedics based on already published papers as well as the techniques and materials used to fabricate 3D-printed objects. Finally, the advantages, current limitations, and future directions of 3D printing in small animal orthopedics have been addressed. 相似文献
83.
Maria Lisa Garavaglia Daniela Giustarini Graziano Colombo Francesco Reggiani Silvia Finazzi Marta Calatroni Lucia Landoni Nicola Marcello Portinaro Aldo Milzani Salvatore Badalamenti Ranieri Rossi Isabella Dalle-Donne 《International journal of molecular sciences》2022,23(5)
Thiols (sulfhydryl groups) are effective antioxidants that can preserve the correct structure of proteins, and can protect cells and tissues from damage induced by oxidative stress. Abnormal levels of thiols have been measured in the blood of patients with moderate-to-severe chronic kidney disease (CKD) compared to healthy subjects, as well as in end-stage renal disease (ESRD) patients on haemodialysis or peritoneal dialysis. The levels of protein thiols (a measure of the endogenous antioxidant capacity inversely related to protein oxidation) and S-thiolated proteins (mixed disulphides of protein thiols and low molecular mass thiols), and the protein thiolation index (the molar ratio of the S-thiolated proteins to free protein thiols in plasma) have been investigated in the plasma or red blood cells of CKD and ESRD patients as possible biomarkers of oxidative stress. This type of minimally invasive analysis provides valuable information on the redox status of the less-easily accessible tissues and organs, and of the whole organism. This review provides an overview of reversible modifications in protein thiols in the setting of CKD and renal replacement therapy. The evidence suggests that protein thiols, S-thiolated proteins, and the protein thiolation index are promising biomarkers of reversible oxidative stress that could be included in the routine monitoring of CKD and ESRD patients. 相似文献
84.
Anna Liguori Alessandro De Vita Giulia Rossi Luisa Stella Dolci Silvia Panzavolta Chiara Gualandi Laura Mercatali Toni Ibrahim Maria Letizia Focarete 《International journal of molecular sciences》2022,23(6)
In the clinical management of solid tumors, the possibility to successfully couple the regeneration of injured tissues with the elimination of residual tumor cells left after surgery could open doors to new therapeutic strategies. In this work, we present a composite hydrogel–electrospun nanofiber scaffold, showing a modular architecture for the delivery of two pharmaceutics with distinct release profiles, that is potentially suitable for local therapy and post-surgical treatment of solid soft tumors. The composite was obtained by coupling gelatin hydrogels to poly(ethylene oxide)/poly(butylene terephthalate) block copolymer nanofibers. Results of the scaffolds’ characterization, together with the analysis of gelatin and drug release kinetics, displayed the possibility to modulate the device architecture to control the release kinetics of the drugs, also providing evidence of their activity. In vitro analyses were also performed using a human epithelioid sarcoma cell line. Furthermore, publicly available expression datasets were interrogated. Confocal imaging showcased the nontoxicity of these devices in vitro. ELISA assays confirmed a modulation of IL-10 inflammation-related cytokine supporting the role of this device in tissue repair. In silico analysis confirmed the role of IL-10 in solid tumors including 262 patients affected by sarcoma as a negative prognostic marker for overall survival. In conclusion, the developed modular composite device may provide a key-enabling technology for the treatment of soft tissue sarcoma. 相似文献
85.
Damaceno Rafael J. P. Rossi Luciano Mugnaini Rogério Mena-Chalco Jesús P. 《Scientometrics》2019,119(1):303-333
Scientometrics - Science can be examined from several standpoints, such as through a bibliometric analysis of the scientific output of researchers, research groups or institutions. However, there... 相似文献
86.
Stringini M Comitini F Taccari M Ciani M 《International journal of food microbiology》2008,127(1-2):184-189
In the present study, we have investigated the occurrence of yeast flora on several agricultural products coming from crop-growing environments in Cameroon, to provide better knowledge of the biodiversity of yeast flora, and to thus define the impact of this biodiversity on food products. The yeast biodiversity was investigated using traditional culture-dependent methods, along with culture-independent methods. The culture-dependent approach was carried out using both direct and enrichment procedures, to detect the broadest possible presence of yeast species. A total of 151 strains belonging to 26 different yeast species were isolated and identified using restriction pattern analysis of the internal transcribed spacer region 5.8S-ITS and sequence analysis of D1/D2 domain of 26S rRNA gene. The enrichment isolation procedures carried out in high-sugar media allowed the recognition of fermentative species such as Saccharomyces cerevisiae and Torulaspora delbrueckii, which have previously not been detected using direct isolation methodology. The results of culture-independent method using DGGE patterns and sequencing of the DNA bands revealed a lower number of yeast species when compared with the culture-dependent methodology even if the identification of several yeast species not detected by traditional microbiological procedures such as Candida tropicalis and Hanseniaspora uvarum is allowed. Thus, these multiphasic approaches to study yeast biodiversity (culture-dependent and -independent methods) have allowed us to get a more complete picture of the microbial diversity in these natural environments. 相似文献
87.
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
88.
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
89.
Effect of a novel soy fermented product enriched with isoflavones and calcium on bone tissue of rats
Bedani R Rossi EA Lepera JS Wang CC de Valdez GF 《Archivos latinoamericanos de nutrición》2006,56(2):146-152
The objective was to evaluate the effect of soy fermented product intake on the corporal weight and bone tissue of ovariectomized mature rats. This product was fermented with Enterococcus faecium and Lactobacillus jugurti and enriched with isoflavones and calcium. The animals were divided in 5 groups: sham-ovariectomized; ovariectomized; ovariectomized treated with soy fermented product enriched with isoflavones and calcium; ovariectomized treated with soy fermented product enriched with calcium and ovariectomized treated with non-fermented product enriched only with calcium. In order to evaluate the effect of the tested product on bone tissue (femur and tibia), the following parameters were analyzed: length; mechanical assay of three points; density (Archimedes principle); mineral content; calcium content; measure of the trabecular widths. The corporal weight of group treated with soy fermented product containing isoflavones and calcium showed no statistical difference from sham-ovariectomized group and trabecular widths tended to have larger than ovariectomized group. However, there was no significant difference to the other evaluated parameters in result of the diverse treatments. Thus, soy fermented product enriched with isoflavones and calcium inhibited the increasing of corporal weight caused by ovariectomy and revealed a tendency to trabecular protection after castration. 相似文献
90.
Induced Defensive Response of Myrtle Oak to Foliar Insect Herbivory in Ambient and Elevated Co2 总被引:2,自引:0,他引:2
The rising level of atmospheric CO2 has stimulated several recent studies attempting to predict the effects of increased CO2 on ecological communities. However, most of these studies have been conducted in the benign conditions of the laboratory and in the absence of herbivores. In the current study, we utilized large octagonal chambers, which enclosed portions of an intact scrub-oak community to investigate the interactive effects of CO2 and insect herbivory on myrtle oak, Quercus myrtifolia. Specifically, we assessed the effects of ambient and elevated CO2 (2x current concentrations) on percent foliar nitrogen, C:N ratio, total relative foliar tannin content, and the presence of leaf damage caused by leaf mining and leaf chewing insects that feed on myrtle oak. Total foliar N declined and C:N ratios increased significantly in oaks in elevated CO2 chambers. The percentages of leaves damaged by either leafminers or leaf chewers tended to be lower in elevated compared to ambient chambers, but they co-occurred on leaves less than expected, regardless of CO2 treatment. Leaves that had been either mined or chewed exhibited a similar wounding or defensive response; they had an average of 25 and 21% higher protein binding ability, which is correlated with tannin concentration, compared to nondamaged control leaves, respectively. While the protein-binding ability (expressed as total percent tannin) of leaves from elevated CO2 was slightly higher than from leaves grown in ambient chambers, this difference was not significant. 相似文献