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   310488篇
  免费   5311篇
  国内免费   839篇
电工技术   5196篇
综合类   182篇
化学工业   50445篇
金属工艺   12240篇
机械仪表   9195篇
建筑科学   7732篇
矿业工程   1890篇
能源动力   7192篇
轻工业   30412篇
水利工程   3426篇
石油天然气   7165篇
武器工业   18篇
无线电   32807篇
一般工业技术   60882篇
冶金工业   54949篇
原子能技术   7603篇
自动化技术   25304篇
  2021年   2779篇
  2019年   2591篇
  2018年   4671篇
  2017年   4626篇
  2016年   5008篇
  2015年   3326篇
  2014年   5298篇
  2013年   14176篇
  2012年   8594篇
  2011年   10733篇
  2010年   8677篇
  2009年   9726篇
  2008年   10020篇
  2007年   9813篇
  2006年   8512篇
  2005年   7844篇
  2004年   7333篇
  2003年   7019篇
  2002年   7056篇
  2001年   6766篇
  2000年   6416篇
  1999年   6494篇
  1998年   15855篇
  1997年   11750篇
  1996年   9033篇
  1995年   6793篇
  1994年   6153篇
  1993年   6033篇
  1992年   4563篇
  1991年   4529篇
  1990年   4360篇
  1989年   4374篇
  1988年   4334篇
  1987年   3659篇
  1986年   3661篇
  1985年   4241篇
  1984年   4030篇
  1983年   3665篇
  1982年   3486篇
  1981年   3631篇
  1980年   3481篇
  1979年   3411篇
  1978年   3479篇
  1977年   4006篇
  1976年   5188篇
  1975年   3173篇
  1974年   3028篇
  1973年   3044篇
  1972年   2658篇
  1971年   2478篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
32.
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   
33.
A hybrid sorbent material for removal of hydrogen sulfide from air was developed. The material is based on activated carbon and iron compounds obtained from waste iron(II) sulfate(VI) heptahydrate. The iron salt is deposited on the carbonaceous support and subjected to oxidation (Fe2+ to Fe3+) using atmospheric oxygen under alkaline conditions. An effect of H2O2 addition to the process on the composition of the resultant material was also examined. X-ray diffraction (XRD) analyses confirmed easy conversion of waste FeSO4·7H2O to iron oxides Fe3O4 and FeOOH. The activated carbon supporting iron oxides revealed a higher efficiency in H2S elimination from air compared to the commercial activated carbon, without any modification.  相似文献   
34.
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   
35.
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   
36.
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   
37.
Urbano  Cristóbal  Ardanuy  Jordi 《Scientometrics》2020,124(1):575-602
Scientometrics - The interdisciplinary nature of library and information science (LIS) research has been highlighted for some time now. The term “interdisciplinary” is used primarily in...  相似文献   
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