首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   8443篇
  免费   514篇
  国内免费   15篇
电工技术   83篇
综合类   2篇
化学工业   1943篇
金属工艺   192篇
机械仪表   177篇
建筑科学   317篇
矿业工程   16篇
能源动力   291篇
轻工业   823篇
水利工程   77篇
石油天然气   29篇
武器工业   6篇
无线电   667篇
一般工业技术   1854篇
冶金工业   854篇
原子能技术   46篇
自动化技术   1595篇
  2023年   67篇
  2022年   53篇
  2021年   192篇
  2020年   192篇
  2019年   153篇
  2018年   224篇
  2017年   254篇
  2016年   309篇
  2015年   206篇
  2014年   327篇
  2013年   715篇
  2012年   511篇
  2011年   613篇
  2010年   432篇
  2009年   427篇
  2008年   556篇
  2007年   471篇
  2006年   409篇
  2005年   321篇
  2004年   304篇
  2003年   267篇
  2002年   227篇
  2001年   134篇
  2000年   111篇
  1999年   123篇
  1998年   128篇
  1997年   104篇
  1996年   88篇
  1995年   100篇
  1994年   109篇
  1993年   77篇
  1992年   65篇
  1991年   54篇
  1990年   48篇
  1989年   63篇
  1988年   48篇
  1987年   26篇
  1986年   33篇
  1985年   43篇
  1984年   44篇
  1983年   27篇
  1982年   27篇
  1981年   48篇
  1980年   26篇
  1979年   23篇
  1978年   26篇
  1977年   17篇
  1975年   15篇
  1974年   23篇
  1973年   17篇
排序方式: 共有8972条查询结果,搜索用时 343 毫秒
1.
Journal of Materials Science - For transformers and inductors to meet the world’s growing demand for electrical power, more efficient soft magnetic materials with high saturation magnetic...  相似文献   
2.
Multimedia Tools and Applications - Changes in appearance present a tremendous problem for the visual localization of an autonomous vehicle in outdoor environments. Data association between the...  相似文献   
3.
Treating neuroinflammation-related injuries and disorders through manipulation of neuroinflammation functions is being heralded as a new therapeutic strategy. In this study, a novel pectic galactan (PG) polysaccharide based gene therapy approach is developed for targeting reactive gliosis in neuroinflammation. Galectin-3 (Gal-3) is a cell protein with a high affinity to β-galactoside sugars and is highly expressed in reactive gliosis. Since PG carries galactans, it can target reactive gliosis via specific carbohydrate interaction between galactan and Gal-3 on the cell membrane, and therefore can be utilized as a carrier for delivering genes to these cells. The carrier is synthesized by modifying quaternary ammonium groups on the PG. The resulting quaternized PG (QPG) is found to form complexes with plasmid DNA with a mean diameter of 100 nm and have the characteristics required for targeted gene therapy. The complexes efficiently condense large amounts of plasmid per particle and successfully bind to Gal-3. The in vivo study shows that the complexes are biocompatible and safe for administration and can selectively transfect reactive glial cells of an induced cortical lesion. The results confirm that this PG-based delivery system is a promising platform for targeting Gal-3 overexpressing neuroinflammation cells for treating neuroinflammation-related injuries and neurodegenerative diseases.  相似文献   
4.
5.
6.
Bile acids have been reported as important cofactors promoting human and murine norovirus (NoV) infections in cell culture. The underlying mechanisms are not resolved. Through the use of chemical shift perturbation (CSP) NMR experiments, we identified a low-affinity bile acid binding site of a human GII.4 NoV strain. Long-timescale MD simulations reveal the formation of a ligand-accessible binding pocket of flexible shape, allowing the formation of stable viral coat protein–bile acid complexes in agreement with experimental CSP data. CSP NMR experiments also show that this mode of bile acid binding has a minor influence on the binding of histo-blood group antigens and vice versa. STD NMR experiments probing the binding of bile acids to virus-like particles of seven different strains suggest that low-affinity bile acid binding is a common feature of human NoV and should therefore be important for understanding the role of bile acids as cofactors in NoV infection.  相似文献   
7.
8.
9.
In the quest for new antibacterial agents, a series of novel long- and medium-chain mono- and disubstituted β-lactones was developed. Their activity against three pathogenic mycobacteria—M. abscessus, M. marinum, and M. tuberculosis—was assessed by the resazurin microtiter assay (REMA). Among the 16 β-lactones synthesized, only 3-hexadecyloxetan-2-one (VM005) exhibited promising activity against M. abscessus, whereas most of the β-lactones showed interesting activities against M. marinum, similar to that of the classical antibiotic, isoniazid. Regarding M. tuberculosis, six compounds were found to be active against this mycobacterium, with β-lactone VM008 [trans-(Z)-3-(hexadec-7-en-1-yl)-4-propyloxetan-2-one] being the best growth inhibitor. The promising antibacterial activities of the best compounds in this series suggest that these molecules may serve as leads for the development of much more efficient antimycobacterial agents.  相似文献   
10.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号