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   5876篇
  免费   196篇
  国内免费   4篇
电工技术   88篇
综合类   3篇
化学工业   729篇
金属工艺   363篇
机械仪表   98篇
建筑科学   180篇
矿业工程   88篇
能源动力   146篇
轻工业   539篇
水利工程   35篇
石油天然气   12篇
无线电   565篇
一般工业技术   940篇
冶金工业   1584篇
原子能技术   57篇
自动化技术   649篇
  2023年   44篇
  2022年   35篇
  2021年   123篇
  2020年   80篇
  2019年   98篇
  2018年   95篇
  2017年   75篇
  2016年   130篇
  2015年   100篇
  2014年   131篇
  2013年   310篇
  2012年   234篇
  2011年   308篇
  2010年   244篇
  2009年   228篇
  2008年   245篇
  2007年   267篇
  2006年   220篇
  2005年   145篇
  2004年   136篇
  2003年   116篇
  2002年   99篇
  2001年   92篇
  2000年   99篇
  1999年   84篇
  1998年   375篇
  1997年   227篇
  1996年   174篇
  1995年   119篇
  1994年   102篇
  1993年   129篇
  1992年   64篇
  1991年   64篇
  1990年   43篇
  1989年   59篇
  1988年   52篇
  1987年   48篇
  1986年   59篇
  1985年   59篇
  1984年   47篇
  1983年   43篇
  1982年   48篇
  1981年   54篇
  1980年   46篇
  1979年   36篇
  1978年   39篇
  1977年   77篇
  1976年   98篇
  1974年   42篇
  1973年   35篇
排序方式: 共有6076条查询结果,搜索用时 0 毫秒
81.
82.
83.
Some indication of the use of Phenidone in PQ developer systems in large scale motion picture laboratory practice is given. Various characteristics, which were examined on a plant scale before MQ systems were abandoned in favour of PQ systems, are discussed; the stabilities and economics of the two systems are compared.  相似文献   
84.
A practical localization technology for underground drift networks—such as those excavated in the practice of underground mining—has yet to become commercially available. This paper focuses on the problem of mapping GPS‐deprived underground environments with the eventual goal of using these maps for navigation. Recent industry‐directed work in the creation of a landmark‐bounded occupancy grid mapping tool that combines odometry, scanning laser data, and sporadically placed passive RFID tags is described. Unlike other work, the suggested approach holds the philosophy that precise localization of the actual landmark locations is not necessary; rather, landmarks serve as a global means for partitioning the map. Successful field experiments were conducted in two underground environments, with the results used to conduct a basic analysis of the described method. © 2012 Wiley Periodicals, Inc.  相似文献   
85.
86.
87.
88.
One of the initial steps of modern drug discovery is the identification of small organic molecules able to inhibit a target macromolecule of therapeutic interest. A small proportion of these hits are further developed into lead compounds, which in turn may ultimately lead to a marketed drug. A commonly used screening protocol used for this task is high-throughput screening (HTS). However, the performance of HTS against antibacterial targets has generally been unsatisfactory, with high costs and low rates of hit identification. Here, we present a novel computational methodology that is able to identify a high proportion of structurally diverse inhibitors by searching unusually large molecular databases in a time-, cost- and resource-efficient manner. This virtual screening methodology was tested prospectively on two versions of an antibacterial target (type II dehydroquinase from Mycobacterium tuberculosis and Streptomyces coelicolor), for which HTS has not provided satisfactory results and consequently practically all known inhibitors are derivatives of the same core scaffold. Overall, our protocols identified 100 new inhibitors, with calculated Ki ranging from 4 to 250 μM (confirmed hit rates are 60% and 62% against each version of the target). Most importantly, over 50 new active molecular scaffolds were discovered that underscore the benefits that a wide application of prospectively validated in silico screening tools is likely to bring to antibacterial hit identification.  相似文献   
89.
90.
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