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   244185篇
  免费   2743篇
  国内免费   856篇
化学   137714篇
晶体学   3471篇
力学   9063篇
综合类   6篇
数学   28331篇
物理学   69199篇
  2021年   2116篇
  2020年   2429篇
  2019年   2703篇
  2018年   3544篇
  2017年   3462篇
  2016年   5015篇
  2015年   3045篇
  2014年   4545篇
  2013年   10802篇
  2012年   8545篇
  2011年   10511篇
  2010年   7103篇
  2009年   6844篇
  2008年   9914篇
  2007年   9995篇
  2006年   9363篇
  2005年   8561篇
  2004年   7585篇
  2003年   6854篇
  2002年   6625篇
  2001年   6306篇
  2000年   5030篇
  1999年   3792篇
  1998年   3300篇
  1997年   3354篇
  1996年   3257篇
  1995年   2628篇
  1994年   2685篇
  1993年   2699篇
  1992年   2823篇
  1991年   2862篇
  1990年   2735篇
  1989年   2714篇
  1988年   2668篇
  1987年   2612篇
  1986年   2516篇
  1985年   3348篇
  1984年   3488篇
  1983年   2769篇
  1982年   3109篇
  1981年   2992篇
  1980年   2769篇
  1979年   2957篇
  1978年   3053篇
  1977年   3053篇
  1976年   3010篇
  1975年   2874篇
  1974年   2862篇
  1973年   3003篇
  1972年   1954篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
32.
33.
The results of investigation of optical image detectors designed for the largest problem, near-VUV, range of the spectrum are presented. The possibility of using a dual-stage image detection system to appreciably lower the sensitivity threshold and make computer data processing feasible is considered. The integration of a UV module into a wideband image detector is studied.  相似文献   
34.
Russian Chemical Bulletin - Quantum chemical calculations and a comparative analysis of Raman spectra of 3,4,5-triphenyl-1-propyl-1,2-diphosphole (1),...  相似文献   
35.
36.
37.
38.
Development of biocompatible porous supports is a promising strategy in the field of tissue engineering for the repair and regeneration of bone tissues with severe damage. Graphene oxide aerogels (GOAs) are excellent candidates for the manufacture of these systems due to their porosity, ability to imitate bone structure, and mechanical resistance, and according to their surface chemical reactivity, they can facilitate osseointegration, osteogenesis, osteoinduction and osteoconduction. In this review, synthesis of GOAs from the most primary source is described, and recent studies on the use of these functionalized carbonaceous foams as scaffolding for bone tissue regeneration are presented.  相似文献   
39.
Russian Journal of General Chemistry - Some new fluoro-heterocyclic compounds containing thiazole and pyridine moities have been synthesized and studied for their antiproliferative activity....  相似文献   
40.
Despite the development of targeted therapies in cancer, the problem of multidrug resistance (MDR) is still unsolved. Most patients with metastatic cancer die from MDR. Transmembrane efflux pumps as the main cause of MDR have been addressed by developed inhibitors, but early inhibitors of the most prominent and longest known efflux pump P-glycoprotein (P-gp) were disappointing. Those inhibitors have been used without knowledge about the expression of P-gp by the treated tumor. Therefore the use of inhibitors of transmembrane efflux pumps in clinical settings is reconsidered as a promising strategy in the case of the respective efflux pump expression. We discovered novel symmetric inhibitors of the symmetric efflux pump MRP4 encoded by the ABCC4 gene. MRP4 is involved in many kinds of cancer with resistance to anticancer drugs. All compounds showed better activities than the best known MRP4 inhibitor MK571 in an MRP4-overexpressing cell line assay, and the activities could be related to the various substitution patterns of aromatic residues within the symmetric molecular framework. One of the best compounds was demonstrated to overcome the MRP4-mediated resistance in the cell line model to restore the anticancer drug sensitivity as a proof of concept.  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