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   307593篇
  免费   5014篇
  国内免费   829篇
电工技术   5438篇
综合类   233篇
化学工业   49896篇
金属工艺   12470篇
机械仪表   9094篇
建筑科学   7864篇
矿业工程   1965篇
能源动力   7051篇
轻工业   28749篇
水利工程   3318篇
石油天然气   7115篇
武器工业   16篇
无线电   32864篇
一般工业技术   62643篇
冶金工业   51832篇
原子能技术   7695篇
自动化技术   25193篇
  2021年   2547篇
  2019年   2313篇
  2018年   4445篇
  2017年   4380篇
  2016年   4773篇
  2015年   3145篇
  2014年   5118篇
  2013年   13703篇
  2012年   7878篇
  2011年   10449篇
  2010年   8602篇
  2009年   9606篇
  2008年   10037篇
  2007年   9842篇
  2006年   8585篇
  2005年   7935篇
  2004年   7306篇
  2003年   7070篇
  2002年   7132篇
  2001年   6922篇
  2000年   6541篇
  1999年   6504篇
  1998年   14973篇
  1997年   11264篇
  1996年   8762篇
  1995年   6696篇
  1994年   6081篇
  1993年   5924篇
  1992年   4604篇
  1991年   4558篇
  1990年   4371篇
  1989年   4389篇
  1988年   4331篇
  1987年   3688篇
  1986年   3674篇
  1985年   4354篇
  1984年   4135篇
  1983年   3742篇
  1982年   3542篇
  1981年   3685篇
  1980年   3537篇
  1979年   3451篇
  1978年   3536篇
  1977年   3997篇
  1976年   5111篇
  1975年   3245篇
  1974年   3069篇
  1973年   3098篇
  1972年   2680篇
  1971年   2507篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
Theoretical Foundations of Chemical Engineering - New research results, as well as those published earlier by the authors, on the synthesis of azo compounds based on nitroanilines obtained by the...  相似文献   
32.
The bromodomain and extra terminal (BET) family of bromodomain-containing proteins (BCPs) have been the subject of extensive research over the past decade, resulting in a plethora of high-quality chemical probes for their tandem bromodomains. In turn, these chemical probes have helped reveal the profound biological role of the BET bromodomains and their role in disease, ultimately leading to a number of molecules in active clinical development. However, the BET subfamily represents just 8/61 of the known human bromodomains, and attention has now expanded to the biological role of the remaining 53 non-BET bromodomains. Rapid growth of this research area has been accompanied by a greater understanding of the requirements for an effective bromodomain chemical probe and has led to a number of new non-BET bromodomain chemical probes being developed. Advances since December 2015 are discussed, highlighting the strengths/caveats of each molecule, and the value they add toward validating the non-BET bromodomains as tractable therapeutic targets.  相似文献   
33.
Seed processing technologies are essential for seed safety and functionality through protection of physicochemical quality, pathogen inactivation, aflatoxin detoxification and alleviation of mutagenicity. Design of a pilot-scale unit of pulsed electric fields (PEF) to treat sesame seeds with respect to quality parameters, Aspergillus parasiticus inactivation and aflatoxin reduction as well as alleviation of aflatoxin mutagenicity were prompted in this study. PEF energy ranged from 0.97 to 17.28 J achieved maximum reductions of peroxide value and acidity number of 67.4 and 85.7%, respectively, and did not change color L*, a*, b* and hue values. A 60% reduction of A. parasiticus counts occurred at the maximum PEF energy. Aflatoxins G1, G2, B1, and B2 contents decreased by 94.7, 92.7, 86.9, and 98.7%, respectively. Except for the samples treated by 2.16 J with 100 μg/plate and by 6.80 J with 10 μg/plate, PEF treatment provided elimination of aflatoxin mutagenity. It is concluded that PEF treatment can be used to treat sesame seeds with preservation of physicochemical properties, inactivation of A. parasiticus and decomposition of aflatoxins with reduced mutagenicity.  相似文献   
34.
Theoretical Foundations of Chemical Engineering - The extraction of nitric and oxalic acids by neutral compounds TBP, DBBP, and TBPO have been studied. The optimal conditions of their separation...  相似文献   
35.
Neural Computing and Applications - This study presents the design of a tenth-order multiple feedback Chebyshev low-pass filter (MF-C-LPF). Component selection and gain calculation of filters are...  相似文献   
36.
37.
38.
39.
40.
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