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   276324篇
  免费   4659篇
  国内免费   844篇
化学   150136篇
晶体学   3738篇
力学   11409篇
综合类   5篇
数学   34854篇
物理学   81685篇
  2021年   2472篇
  2020年   2841篇
  2019年   2998篇
  2018年   3954篇
  2017年   3657篇
  2016年   5877篇
  2015年   4216篇
  2014年   5610篇
  2013年   13287篇
  2012年   11915篇
  2011年   13874篇
  2010年   8891篇
  2009年   8327篇
  2008年   12333篇
  2007年   12527篇
  2006年   11805篇
  2005年   10796篇
  2004年   9713篇
  2003年   8461篇
  2002年   7991篇
  2001年   7560篇
  2000年   5926篇
  1999年   4582篇
  1998年   3691篇
  1997年   3687篇
  1996年   3657篇
  1995年   3190篇
  1994年   3049篇
  1993年   2910篇
  1992年   3276篇
  1991年   3177篇
  1990年   3048篇
  1989年   2853篇
  1988年   2871篇
  1987年   2850篇
  1986年   2629篇
  1985年   3602篇
  1984年   3832篇
  1983年   3061篇
  1982年   3363篇
  1981年   3356篇
  1980年   3151篇
  1979年   3227篇
  1978年   3285篇
  1977年   3211篇
  1976年   3318篇
  1975年   3079篇
  1974年   3052篇
  1973年   3178篇
  1972年   1932篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
52.
53.
54.
55.
56.
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   
57.
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   
58.
Sybachin  A. V.  Stepanova  D. A. 《Colloid Journal》2021,83(4):531-531
Colloid Journal - An Erratum to this paper has been published: https://doi.org/10.1134/S1061933X21330024  相似文献   
59.
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   
60.
A photoluminescent bimetallic cluster [Ag10Cu6(bdppthi)2(C≡CPh)12(MeOH)2(H2O)](ClO4)4 ( 1 , bdppthi=N,N’-bis(diphenylphosphanylmethyl)-tetrahydroimidazole} was synthesized from the PNNP type ligand bdppthi generated in-situ. Upon excitation at 365 nm, 1 exhibited strong phosphorescent emission at 630 nm, which was selectively quenched by NH3 in air or water. The sensing of NH3 was rapid and recoverable, with detection limits of 53 ppm (v/v) in N2 and 21 μmol/L (0.36 ppm, w/w) for NH3 ⋅ H2O in water. Cluster 1 could potentially serve as a bifunctional chemical sensor for the efficient detection of ammonia in waste-gas and waste-water.  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