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   1536646篇
  免费   27550篇
  国内免费   7059篇
电工技术   34439篇
综合类   6452篇
化学工业   271610篇
金属工艺   64880篇
机械仪表   43056篇
建筑科学   46701篇
矿业工程   11392篇
能源动力   50359篇
轻工业   115281篇
水利工程   15648篇
石油天然气   37461篇
武器工业   135篇
无线电   197208篇
一般工业技术   288109篇
冶金工业   184271篇
原子能技术   33992篇
自动化技术   170261篇
  2021年   15636篇
  2020年   11919篇
  2019年   14666篇
  2018年   15876篇
  2017年   15112篇
  2016年   21441篇
  2015年   17418篇
  2014年   28784篇
  2013年   88124篇
  2012年   35930篇
  2011年   48491篇
  2010年   42758篇
  2009年   50911篇
  2008年   45379篇
  2007年   42457篇
  2006年   45067篇
  2005年   39690篇
  2004年   41959篇
  2003年   41841篇
  2002年   40808篇
  2001年   38057篇
  2000年   36310篇
  1999年   35901篇
  1998年   51489篇
  1997年   42944篇
  1996年   37925篇
  1995年   32272篇
  1994年   30177篇
  1993年   29949篇
  1992年   26489篇
  1991年   23826篇
  1990年   23954篇
  1989年   23077篇
  1988年   21646篇
  1987年   19838篇
  1986年   19251篇
  1985年   22508篇
  1984年   22492篇
  1983年   20492篇
  1982年   19436篇
  1981年   19559篇
  1980年   18191篇
  1979年   18675篇
  1978年   17897篇
  1977年   18150篇
  1976年   20216篇
  1975年   16153篇
  1974年   15618篇
  1973年   15693篇
  1972年   13153篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
871.
872.
Class I hydrophobin Vmh2, a peculiar surface active and versatile fungal protein, is known to self‐assemble into chemically stable amphiphilic films, to be able to change wettability of surfaces, and to strongly adsorb other proteins. Herein, a fast, highly homogeneous and efficient glass functionalization by spontaneous self‐assembling of Vmh2 at liquid–solid interfaces is achieved (in 2 min). The Vmh2‐coated glass slides are proven to immobilize not only proteins but also nanomaterials such as graphene oxide (GO) and quantum dots (QDs). As models, bovine serum albumin labeled with Alexa 555 fluorophore, anti‐immunoglobulin G antibodies, and cadmium telluride QDs are patterned in a microarray fashion in order to demonstrate functionality, reproducibility, and versatility of the proposed substrate. Additionally, a GO layer is effectively and homogeneously self‐assembled onto the studied functionalized surface. This approach offers a quick and simple alternative to immobilize nanomaterials and proteins, which is appealing for new bioanalytical and nanobioenabled applications.  相似文献   
873.
874.
875.
876.
877.
878.
Bruton's tyrosine kinase (Btk) is an attractive target for the treatment of a wide array of B-cell malignancies and autoimmune diseases. Small-molecule covalent irreversible Btk inhibitors targeting Cys481 have been developed for the treatment of such diseases. In clinical trials, probe molecules are required in occupancy studies to measure the level of engagement of the protein by these covalent irreversible inhibitors. The result of this pharmacodynamic (PD) activity provides guidance for appropriate dosage selection to optimize inhibition of the drug target and correlation of target inhibition with disease treatment efficacy. This information is crucial for successful evaluation of drug candidates in clinical trials. Based on the pyridine carboxamide scaffold of a novel solvent-accessible pocket (SAP) series of covalent irreversible Btk inhibitors, we successfully developed a potent and selective affinity-based biotinylated probe 12 (2-[(4-{4-[5-(1-{5-[(3aS,4S,6aR)-2-oxo-hexahydro-1H-thieno[3,4-d]imidazol-4-yl]pentanamido}-3,6,9,12-tetraoxapentadecan-15-amido)pentanoyl]piperazine-1-carbonyl}phenyl)amino]-6-[1-(prop-2-enoyl)piperidin-4-yl]pyridine-3-carboxamide). Compound 12 has been used in Btk occupancy assays for preclinical studies to determine the therapeutic efficacy of Btk inhibition in two mouse lupus models driven by TLR7 activation and type I interferon.  相似文献   
879.
880.
Bulge is a defect that causes geometrical inaccuracy and premature failure in the innovative incremental sheet forming (ISF) process. This study has two-fold objectives: (1) knowing the bulging behavior of a Cu clad tri-layered steel sheet as a function of forming conditions, and (2) analyzing the bending effect on bulging in an attempt to identify the associated mechanism. A series of ISF tests and bending analysis are performed to realize these objectives. From the cause-effect analysis, it is found that bulge formation in the layered sheet is sensitive to forming conditions in a way that bulging can be minimized utilizing annealed material and performing ISF with larger tool diameter and step size. The bending under tension analysis reveals that the formation of bulge is an outgrowth of bending moment that the forming tool applies on the sheet during ISF. Furthermore, the magnitude of bending moment depending upon the forming conditions varies from 0.046 to 10.24 N·m/m and causes a corresponding change in the mean bulge height from 0.07 to 0.91 mm. The bending moment governs bulging in layered sheet through a linear law. These findings lead to a conclusion that the bulge defect can be overcome by controlling the bending moment and the formula proposed can be helpful in this regards.  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