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   288011篇
  免费   5818篇
  国内免费   2024篇
电工技术   6469篇
技术理论   6篇
综合类   2262篇
化学工业   42086篇
金属工艺   12053篇
机械仪表   10273篇
建筑科学   8330篇
矿业工程   1863篇
能源动力   7173篇
轻工业   24502篇
水利工程   3046篇
石油天然气   5836篇
武器工业   227篇
无线电   37811篇
一般工业技术   53619篇
冶金工业   48010篇
原子能技术   5799篇
自动化技术   26488篇
  2021年   3060篇
  2020年   2306篇
  2019年   2692篇
  2018年   4211篇
  2017年   4352篇
  2016年   4541篇
  2015年   3303篇
  2014年   5376篇
  2013年   12898篇
  2012年   8222篇
  2011年   10786篇
  2010年   8696篇
  2009年   9502篇
  2008年   10238篇
  2007年   10023篇
  2006年   9206篇
  2005年   8408篇
  2004年   7840篇
  2003年   7708篇
  2002年   7414篇
  2001年   7482篇
  2000年   6958篇
  1999年   7110篇
  1998年   14943篇
  1997年   10824篇
  1996年   8621篇
  1995年   6831篇
  1994年   6074篇
  1993年   5843篇
  1992年   4758篇
  1991年   4360篇
  1990年   4165篇
  1989年   3879篇
  1988年   3694篇
  1987年   3217篇
  1986年   3116篇
  1985年   3632篇
  1984年   3411篇
  1983年   3056篇
  1982年   2870篇
  1981年   2970篇
  1980年   2769篇
  1979年   2660篇
  1978年   2504篇
  1977年   2949篇
  1976年   3567篇
  1975年   2320篇
  1974年   2314篇
  1973年   2322篇
  1972年   1852篇
排序方式: 共有10000条查询结果,搜索用时 250 毫秒
61.
Combined photochemical arylation, “nuisance effect” (SNAr) reaction sequences have been employed in the design of small arrays for immediate deployment in medium-throughput X-ray protein–ligand structure determination. Reactions were deliberately allowed to run “out of control” in terms of selectivity; for example the ortho-arylation of 2-phenylpyridine gave five products resulting from mono- and bisarylations combined with SNAr processes. As a result, a number of crystallographic hits against NUDT7, a key peroxisomal CoA ester hydrolase, have been identified.  相似文献   
62.
63.
64.
65.
66.
Dietary advanced glycation end products (dAGEs) are complex and heterogeneous compounds derived from nonenzymatic glycation reactions during industrial processing and home cooking. There is mounting evidence showing that dAGEs are closely associated with various chronic diseases, where the absorbed dAGEs fuel the biological AGEs pool to exhibit noxious effects on human health. Currently, due to the uncertain bioavailability and rapid renal clearance of dAGEs, the relationship between dAGEs and biological AGEs remains debatable. In this review, we provide the most updated information on dAGEs including their generation in processed foods, analytical and characterization techniques, metabolic fates, interaction with AGE receptors, implications on human health and reducing strategies. Available evidence demonstrating a relevance between dAGEs and food allergy is also included. AGEs are ubiquitous in foods and their contents largely depend on the reactivity of carbonyl and amino groups, along with surrounding condition mainly pH and heating procedures. Once being digested and absorbed into the circulation, two separate pathways can be involved in the deleterious effects of dAGEs: an AGE receptor‐dependent way to stimulate cell signals, and an AGE receptor‐independent way to dysregulate proteins via forming complexes. Inhibition of AGEs formation during food processing and reduction in the diet are two potent approaches to restrict health‐hazardous dAGEs. To elucidate the biological role of dAGEs toward human health, the following significant perspectives are raised: molecular size and complexity of dAGEs; interactions between unabsorbed dAGEs and gut microbiota; and roles played by concomitant compounds in the heat‐processed foods.  相似文献   
67.
68.
Lund  Brady D.  Maurya  Sanjay Kumar 《Scientometrics》2020,125(3):2491-2504
Scientometrics - This study investigates a potential relationship between highly-cited scholarly papers and the number of citations received by other papers with which they share a journal issue....  相似文献   
69.
Morozov  Yu. D.  Pemov  I. F.  Matrosov  M. Yu.  Zin’ko  B. F. 《Metallurgist》2020,63(9-10):933-950
Metallurgist - We consider domestic and foreign standards for rolled metals used in bridge building. Domestic standards contain elevated requirements to the reliability of rolled metals in terms of...  相似文献   
70.
Russian Journal of Non-Ferrous Metals - This article is devoted to the influence of sodium lignosulfonate (SL), anionic surfactants (sodium dodecylsulfate (SDS), sodium dodecylbenzene sulfonate...  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