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   786588篇
  免费   8511篇
  国内免费   2205篇
化学   402125篇
晶体学   11516篇
力学   38774篇
综合类   17篇
数学   105750篇
物理学   239122篇
  2021年   6541篇
  2020年   7293篇
  2019年   8298篇
  2018年   11119篇
  2017年   10998篇
  2016年   15990篇
  2015年   9424篇
  2014年   15228篇
  2013年   35329篇
  2012年   27029篇
  2011年   32823篇
  2010年   23893篇
  2009年   23873篇
  2008年   30449篇
  2007年   30181篇
  2006年   27811篇
  2005年   24852篇
  2004年   23115篇
  2003年   20709篇
  2002年   20747篇
  2001年   22224篇
  2000年   17268篇
  1999年   13492篇
  1998年   11607篇
  1997年   11284篇
  1996年   10724篇
  1995年   9764篇
  1994年   9654篇
  1993年   9475篇
  1992年   10229篇
  1991年   10534篇
  1990年   10183篇
  1989年   10029篇
  1988年   9895篇
  1987年   9756篇
  1986年   9170篇
  1985年   11887篇
  1984年   12226篇
  1983年   10073篇
  1982年   10568篇
  1981年   10158篇
  1980年   9616篇
  1979年   10365篇
  1978年   10751篇
  1977年   10610篇
  1976年   10801篇
  1975年   9848篇
  1974年   9856篇
  1973年   10181篇
  1972年   7404篇
排序方式: 共有10000条查询结果,搜索用时 209 毫秒
21.
Aequationes mathematicae - In this paper, we establish a new class of dynamic inequalities of Hardy’s type which generalize and improve some recent results given in the literature. More...  相似文献   
22.
Russian Journal of Applied Chemistry - Recent achievements in the field of the development of preparation methods and study of structure and properties of epoxy nanocomposites with metal-containing...  相似文献   
23.
Aqueous self-assembly of short peptides has attracted growing attention for the construction of supramolecular materials for various bioapplications. Herein, we describe how the thermolysin-assisted biocatalytic construction of a dipeptide hydrazide from an N-protected amino acid and an amino acid hydrazide leads to the formation of thermally stable supramolecular hydrogels. In addition, we demonstrate the post-assembly modification of the supramolecular architectures constructed in situ tethering hydrazide groups as a chemical handle by means of fluorescence imaging.  相似文献   
24.
Journal of Structural Chemistry - Atomic and electronic structures of cyclic organosilicon compound 9,9,10,10-tetraethynyl-9,10-dihydrodisilaanthracene are studied by the density functional theory....  相似文献   
25.
Journal of Experimental and Theoretical Physics - The surface current density of charge carriers in two-dimensional doubly periodic n-type semiconductor superlattices in an external magnetic field...  相似文献   
26.
Theoretical and Mathematical Physics - We study a phenomenological model in which dark matter in the cosmological constant form is identified with the mean energy–momentum tensor of a...  相似文献   
27.
Russian Journal of General Chemistry - The review article traces the main trends of the synthetic approach to the solution of the problem of overcoming the resistance of pathogenic bacterial...  相似文献   
28.
Knyazev  Yu. V.  Kazak  N. V.  Gavrichkov  V. A.  Polukeev  S. I.  Ovchinnikov  S. G. 《JETP Letters》2022,116(8):567-573
JETP Letters - Changes in the magnetic properties of FeBO3 single crystals in the course of spin crossover occurring with increasing pressure up to 63 GPa are studied both experimentally and...  相似文献   
29.
Chemistry of Heterocyclic Compounds - 2-Imino-2,5-dihydrofurans are a highly valuable class of heterocyclic compounds that show versatile biological activity and are used in diverse fields of...  相似文献   
30.
Low-flow chromatography has a rich history of innovation but has yet to reach widespread implementation in bioanalytical applications. Improvements in pump technology, microfluidic connections, and nano-electrospray sources for MS have laid the groundwork for broader application, and innovation in this space has accelerated in recent years. This article reviews the instrumentation used for nano-flow LC, the types of columns employed, and strategies for multidimensionality of separations, which are key to the future state of the technique to the high-throughput needs of modern bioanalysis. An update of the current applications where nano-LC is widely used, such as proteomics and metabolomics, is discussed. But the trend toward biopharmaceutical development of increasingly complex, targeted, and potent therapeutics for the safe treatment of disease drives the need for ultimate selectivity and sensitivity of our analytical platforms for targeted quantitation in a regulated space. The selectivity needs are best addressed by mass spectrometric detection, especially at high resolutions, and exquisite sensitivity is provided by nano-electrospray ionization as the technology continues to evolve into an accessible, robust, and easy-to-use platform.  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