全文获取类型
收费全文 | 9861篇 |
免费 | 362篇 |
国内免费 | 20篇 |
专业分类
电工技术 | 145篇 |
综合类 | 18篇 |
化学工业 | 2478篇 |
金属工艺 | 179篇 |
机械仪表 | 218篇 |
建筑科学 | 381篇 |
矿业工程 | 36篇 |
能源动力 | 246篇 |
轻工业 | 410篇 |
水利工程 | 82篇 |
石油天然气 | 49篇 |
无线电 | 849篇 |
一般工业技术 | 2438篇 |
冶金工业 | 1008篇 |
原子能技术 | 99篇 |
自动化技术 | 1607篇 |
出版年
2024年 | 110篇 |
2023年 | 191篇 |
2022年 | 374篇 |
2021年 | 461篇 |
2020年 | 365篇 |
2019年 | 321篇 |
2018年 | 310篇 |
2017年 | 259篇 |
2016年 | 378篇 |
2015年 | 299篇 |
2014年 | 442篇 |
2013年 | 556篇 |
2012年 | 559篇 |
2011年 | 629篇 |
2010年 | 440篇 |
2009年 | 418篇 |
2008年 | 444篇 |
2007年 | 420篇 |
2006年 | 329篇 |
2005年 | 254篇 |
2004年 | 224篇 |
2003年 | 205篇 |
2002年 | 193篇 |
2001年 | 127篇 |
2000年 | 119篇 |
1999年 | 120篇 |
1998年 | 195篇 |
1997年 | 157篇 |
1996年 | 109篇 |
1995年 | 84篇 |
1994年 | 76篇 |
1993年 | 94篇 |
1992年 | 60篇 |
1991年 | 56篇 |
1990年 | 55篇 |
1989年 | 42篇 |
1988年 | 48篇 |
1987年 | 45篇 |
1986年 | 38篇 |
1985年 | 46篇 |
1984年 | 44篇 |
1983年 | 37篇 |
1982年 | 31篇 |
1981年 | 33篇 |
1980年 | 27篇 |
1978年 | 36篇 |
1977年 | 30篇 |
1976年 | 69篇 |
1975年 | 30篇 |
1974年 | 27篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
Anna Carla Culla Corina Vater Xinggui Tian Julia Bolte Tilman Ahlfeld Henriette Bretschneider Alexander Pape Stuart B. Goodman Michael Gelinsky Stefan Zwingenberger 《International journal of molecular sciences》2022,23(6)
To treat critical-size bone defects, composite materials and tissue-engineered bone grafts play important roles in bone repair materials. The purpose of this study was to investigate the bone regenerative potential of hybrid scaffolds consisting of macroporous calcium phosphate cement (CPC) and microporous mineralized collagen matrix (MCM). Hybrid scaffolds were synthetized by 3D plotting CPC and then filling with MCM (MCM-CPC group) and implanted into a 5 mm critical size femoral defect in rats. Defects left empty (control group) as well as defects treated with scaffolds made of CPC only (CPC group) and MCM only (MCM group) served as controls. Eight weeks after surgery, micro-computed tomography scans and histological analysis were performed to analyze the newly formed bone, the degree of defect healing and the activity of osteoclasts. Mechanical stability was tested by 3-point-bending of the explanted femora. Compared with the other groups, more newly formed bone was found within MCM-CPC scaffolds. The new bone tissue had a clamp-like structure which was fully connected to the hybrid scaffolds and thereby enhanced the biomechanical strength. Together, the biomimetic hybrid MCM-CPC scaffolds enhanced bone defect healing by improved osseointegration and their differentiated degradation provides spatial effects in the process of critical-bone defect healing. 相似文献
993.
Cai Hui Yu Yiling Lin Yu-Chuan Puretzky Alexander A. Geohegan David B. Xiao Kai 《Nano Research》2021,14(6):1625-1649
Nano Research - Two-dimensional (2D) materials hold great promise for applications in optoelectronics, quantum information science, and energy conversion due to their remarkable properties imbued... 相似文献
994.
Rokas Lukosevicius Simonas Juzenas Violeta Salteniene Ugne Kulokiene Justina Arstikyte Georg Hemmrich-Stanisak Andre Franke Alexander Link Paulius Ruzgys Saulius Satkauskas Henrikas Pauzas Tadas Latkauskas Gediminas Kiudelis Francesc Balaguer Juozas Kupcinskas Jurgita Skieceviciene 《International journal of molecular sciences》2022,23(4)
Regulatory changes occurring early in colorectal cancer development remain poorly investigated. Since the majority of cases develop from polyps in the adenoma-carcinoma transition, a search of early molecular features, such as aberrations in miRNA expression occurring prior to cancer development, would enable identification of potentially causal, rather than consequential, candidates in the progression of polyp to cancer. In the current study, by employing small RNA-seq profiling of colon biopsy samples, we described differentially expressed miRNAs and their isoforms in the adenoma-carcinoma transition. Analysis of healthy-adenoma-carcinoma sequence in an independent validation group enabled us to identify early deregulated miRNAs including hsa-miR-1246 and hsa-miR-215-5p, the expressions of which are, respectively, gradually increasing and decreasing. Loss-of-function experiments revealed that inhibition of hsa-miR-1246 lead to reduced cell viability, colony formation, and migration rate, thereby indicating an oncogenic effect of this miRNA in vitro. Subsequent western blot and luciferase reporter assay provided evidence of hsa-miR-1246 being involved in the regulation of target AXIN2 and CFTR genes’ expression. To conclude, the present study revealed possible involvement of hsa-miR-1246 in early colorectal cancer development and regulation of tumor suppressors AXIN2 and CFTR. 相似文献
995.
Atherosclerosis is a multicausal disease characterized by the formation of cholesterol-containing plaque in the pronounced intima nearest to the heart’s elastic-type arteries that have high levels of blood circulation. Plaques are formed due to arterial pressure-induced damage to the endothelium in areas of turbulent blood flow. It is found in the majority of the Western population, including young people. This denies the monogenic mechanism of atherogenesis. In 1988, Orekhov et al. and Kawai et al. discovered that the presence of atherogenic (modified, including oxidized ones) LDLs is necessary for atherogenesis. On the basis of our discovery, suggesting that the overloading of enterocytes with lipids could lead to the formation of modified LDLs, we proposed a new hypothesis explaining the main factors of atherogenesis. Indeed, when endothelial cells are damaged and then pass through the G2 phase of their cell cycle they secrete proteins into their basement membrane. This leads to thickening of the basement membrane and increases its affinity to LDL especially for modified ones. When the enterocyte transcytosis pathway is overloaded with fat, very large chylomicrons are formed, which have few sialic acids, circulate in the blood for a long time, undergo oxidation, and can induce the production of autoantibodies. It is the sialic acids that shield the short forks of the polysaccharide chains to which autoantibodies are produced. Here, these data are evaluated from the point of view of our new model. 相似文献
996.
Manuel Gacitúa Alexander Carreo Rosaly Morales-Guevara Dayn Pez-Hernndez Jorge I. Martínez-Araya Eyleen Araya Marcelo Preite Carolina Otero María Macarena Rivera-Zaldívar Andrs Silva Juan A. Fuentes 《International journal of molecular sciences》2022,23(5)
Searching for adequate and effective compounds displaying antimicrobial activities, especially against Gram-positive bacteria, is an important research area due to the high hospitalization and mortality rates of these bacterial infections in both the human and veterinary fields. In this work, we explored (E)-4-amino-3-((3,5-di-tert-butyl-2-hydroxybenzylidene)amino) benzoic acid (SB-1, harboring an intramolecular hydrogen bond) and (E)-2-((4-nitrobenzilidene)amino)aniline (SB-2), two Schiff bases derivatives. Results demonstrated that SB-1 showed an antibacterial activity determined by the minimal inhibitory concentration (MIC) against Staphylococcus aureus, Enterococcus faecalis, and Bacillus cereus (Gram-positive bacteria involved in human and animal diseases such as skin infections, pneumonia, diarrheal syndrome, and urinary tract infections, among others), which was similar to that shown by the classical antibiotic chloramphenicol. By contrast, this compound showed no effect against Gram-negative bacteria (Klebsiella pneumoniae, Escherichia coli, and Salmonella enterica). Furthermore, we provide a comprehensive physicochemical and theoretical characterization of SB-1 (as well as several analyses for SB-2), including elemental analysis, ESMS, 1H and 13C NMR (assigned by 1D and 2D techniques), DEPT, UV-Vis, FTIR, and cyclic voltammetry. We also performed a computational study through the DFT theory level, including geometry optimization, TD-DFT, NBO, and global and local reactivity analyses. 相似文献
997.
998.
Yana Danailova Tsvetelina Velikova Georgi Nikolaev Zorka Mitova Alexander Shinkov Hristo Gagov Rossitza Konakchieva 《International journal of molecular sciences》2022,23(9)
Since the thyroid gland is one of the organs most affected by autoimmune processes, many patients with thyroiditis of Hashimoto (TH) seek medical advice on lifestyle variance and dietary modifications to improve and maintain their hyroid function. In this review, we aim to present and discuss some challenges associated with the nutritional management of TH, focusing on environmental and dietary deficits, inflammatory and toxic nutrients, cyanotoxins, etc. We discuss the relationships among different diets, chronic inflammation, and microbiota, and their impact on the development and exacerbation of TH in detail. We share some novel insights into the role of vitamin D and melatonin for preserving thyroid function during chronic inflammation in autoimmune predisposed subjects. A comprehensive overview is provided on anti-inflammatory nutrients and ecological diets, including foods for cleansing and detoxification, which represent strategies to prevent relapses and achieve overall improvement of life quality. In conclusion, data from biomedical and clinical studies provide evidence that an appropriate dietary and lighting regimen could significantly improve the function of the thyroid gland and reduce the reactivity of autoantibodies in TH. Compliance with nutritional guidelines may help TH patients to reduce the need for medicines. 相似文献
999.
Alexander Blagov Elena B. Zhigmitova Margarita A. Sazonova Liudmila M. Mikhaleva Vladislav Kalmykov Nikolay K. Shakhpazyan Varvara A. Orekhova Alexander N. Orekhov 《International journal of molecular sciences》2022,23(9)
Crohn’s disease remains one of the challenging problems of modern medicine, and the development of new and effective and safer treatments against it is a dynamic field of research. To make such developments possible, it is important to understand the pathologic processes underlying the onset and progression of Crohn’s disease at the molecular and cellular levels. During the recent years, the involvement of mitochondrial dysfunction and associated chronic inflammation in these processes became evident. In this review, we discuss the published works on pathogenetic models of Crohn’s disease. These models make studying the role of mitochondrial dysfunction in the disease pathogenesis possible and advances the development of novel therapies. 相似文献
1000.
Ravichandran Ramasamy Alexander Shekhtman Ann Marie Schmidt 《International journal of molecular sciences》2022,23(9)
Increasing evidence links the RAGE (receptor for advanced glycation end products)/DIAPH1 (Diaphanous 1) signaling axis to the pathogenesis of diabetic complications. RAGE is a multi-ligand receptor and through these ligand–receptor interactions, extensive maladaptive effects are exerted on cell types and tissues targeted for dysfunction in hyperglycemia observed in both type 1 and type 2 diabetes. Recent evidence indicates that RAGE ligands, acting as damage-associated molecular patterns molecules, or DAMPs, through RAGE may impact interferon signaling pathways, specifically through upregulation of IRF7 (interferon regulatory factor 7), thereby heralding and evoking pro-inflammatory effects on vulnerable tissues. Although successful targeting of RAGE in the clinical milieu has, to date, not been met with success, recent approaches to target RAGE intracellular signaling may hold promise to fill this critical gap. This review focuses on recent examples of highlights and updates to the pathobiology of RAGE and DIAPH1 in diabetic complications. 相似文献