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   1439083篇
  免费   27126篇
  国内免费   6971篇
电工技术   33816篇
综合类   6457篇
化学工业   252968篇
金属工艺   63633篇
机械仪表   41122篇
建筑科学   42091篇
矿业工程   11419篇
能源动力   49738篇
轻工业   106117篇
水利工程   14575篇
石油天然气   36755篇
武器工业   153篇
无线电   194321篇
一般工业技术   274396篇
冶金工业   145391篇
原子能技术   34015篇
自动化技术   166213篇
  2021年   14472篇
  2020年   11747篇
  2019年   14513篇
  2018年   15489篇
  2017年   14808篇
  2016年   21032篇
  2015年   17246篇
  2014年   28555篇
  2013年   87526篇
  2012年   34483篇
  2011年   46673篇
  2010年   42085篇
  2009年   50708篇
  2008年   43754篇
  2007年   40920篇
  2006年   43925篇
  2005年   38736篇
  2004年   40768篇
  2003年   40090篇
  2002年   37865篇
  2001年   34085篇
  2000年   32146篇
  1999年   31274篇
  1998年   36441篇
  1997年   33339篇
  1996年   30446篇
  1995年   28834篇
  1994年   27129篇
  1993年   27010篇
  1992年   25325篇
  1991年   22396篇
  1990年   22913篇
  1989年   21825篇
  1988年   20284篇
  1987年   18699篇
  1986年   18118篇
  1985年   21488篇
  1984年   21837篇
  1983年   19802篇
  1982年   18868篇
  1981年   18920篇
  1980年   17612篇
  1979年   18178篇
  1978年   17442篇
  1977年   17058篇
  1976年   17682篇
  1975年   15752篇
  1974年   15302篇
  1973年   15396篇
  1972年   12932篇
排序方式: 共有10000条查询结果,搜索用时 218 毫秒
31.
32.
33.
34.
Protection of Metals and Physical Chemistry of Surfaces - The anti-corrosive Zn and Zn–Ni alloy coatings were electrodeposited on different copper substrates using an optimized sulphate...  相似文献   
35.
Protection of Metals and Physical Chemistry of Surfaces - Impedance spectroscopy was used to study the adsorption of the IFKhAN-92 inhibitor, a triazole derivative, on cathodically polarized...  相似文献   
36.
Understanding the ligandability of a target protein, defined as the capability of a protein to bind drug-like compounds on any site, can give important stimuli to drug-development projects. For instance, inhibition of protein–protein interactions usually depends on the identification of protein surface binders. DNA-encoded chemical libraries (DELs) allow scanning of protein surfaces with large chemical space. Encoded library selection screens uncovered several protein–protein interaction inhibitors and compounds binding to the surface of G protein-coupled receptors (GPCRs) and kinases. The protein surface-binding chemotypes from DELs are predominantly chemically modified and cyclized peptides, and functional small-molecule peptidomimetics. Peptoid libraries and structural peptidomimetics have been less studied in the DEL field, hinting at hitherto less populated chemical space and suggesting alternative library designs. Roughly a third of bioactive molecules evolved from smaller, target-focused libraries. They showcase the potential of encoded libraries to identify more potent molecules from weak, for example, fragment-like, starting points.  相似文献   
37.
Amides from indole-3-glyoxylic acid and 4-benzoyl-2-methylpiperazine, which are related to entry inhibitors developed by Bristol-Myers Squibb (BMS), have been synthesized with aliphatic chains located at the C7 position of the indole ring. These spacers contain an azido group suitable for the well-known Cu(I)-catalyzed (3+2)-cycloaddition or an activated triple bond for the nucleophilic addition of thiols under physiological conditions. Reaction with polyols (β-cyclodextrin and hyperbranched polyglycerol) decorated with complementary click partners has afforded polyol-BMS-like conjugates that are not cytotoxic (TZM.bl cells) and retain the activity against R5-HIV-1NLAD8 isolates. Thus, potential vaginal microbicides based on entry inhibitors, which can be called of 4th generation, are reported here for the first time.  相似文献   
38.
PRO teolysis TA rgeting C himeras (PROTACs) promote the degradation, rather than inhibition, of a drug target as a mechanism for therapeutic treatment. Bifunctional PROTAC molecules allow simultaneous binding of both the target protein and an E3-Ubiquitin ligase, bringing the two proteins into close spatial proximity to allow ubiquitinylation and degradation of the target protein via the cell's endogenous protein degradation pathway. We utilized native mass spectrometry (MS) to study the ternary complexes promoted by the previously reported PROTAC GNE-987 between Brd4 bromodomains 1 and 2, and Von Hippel Lindeau E3-Ubiquitin Ligase. Native MS at high resolution allowed us to measure ternary complex formation as a function of PROTAC concentration to provide a measure of complex affinity and stability, whilst simultaneously measuring other intermediate protein species. Native MS provides a high-throughput, low sample consumption, direct screening method to measure ternary complexes for PROTAC development.  相似文献   
39.
An improved glucose-chelator-albumin bioconjugate (GluCAB) derivative, GluCAB-2Mal, has been synthesized and studied for in vivo 64Cu-PET/CT imaging in breast cancer mice models together with its first-generation analogue GluCAB-1Mal. The radioligand works on the principle of tumor targeting through the enhanced permeability and retention (EPR) effect with a supportive role played by glucose metabolism. [64Cu]Cu-GluCAB-2Mal (99 % RCP) exhibited high serum stability with immediate binding to serum proteins. In vivo experiments for comparison between tumor targeting of [64Cu]Cu-GluCAB-2Mal and previous-generation [64Cu]Cu-GluCAB-1Mal encompassed microPET/CT imaging and biodistribution analysis in an allograft E0771 breast cancer mouse model. Tumor uptake of [64Cu]Cu-GluCAB-2Mal was clearly evident with twice as much accumulation as compared to its predecessor and a tumor/muscle ratio of up to 5 after 24 h. Further comparison indicated a decrease in liver accumulation for [64Cu]Cu-Glu-CAB-2Mal.  相似文献   
40.
The G protein-coupled receptor GPR183/EBI2, which is activated by oxysterols, is a therapeutic target for inflammatory and metabolic diseases where both antagonists and agonists are of potential interest. Using the piperazine diamide core of the known GPR183 antagonist (E)-3-(4-bromophenyl)-1-(4-(4-methoxybenzoyl)piperazin-1-yl)prop-2-en-1-one (NIBR189) as starting point, we identified and sourced 79 structurally related compounds that were commercially available. In vitro screening of this compound collection using a Ca2+ mobilization assay resulted in the identification of 10 compounds with agonist properties. To enable establishment of initial structure-activity relationship trends, these were supplemented with five in-house compounds, two of which were also shown to be GPR183 agonists. Taken together, our findings suggest that the agonist activity of this compound series is dictated by the substitution pattern of one of the two distal phenyl rings, which functions as a molecular efficacy-switch.  相似文献   
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