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   682940篇
  免费   6533篇
  国内免费   1898篇
化学   344062篇
晶体学   10529篇
力学   33460篇
综合类   11篇
数学   93678篇
物理学   209631篇
  2020年   4772篇
  2019年   5484篇
  2018年   12980篇
  2017年   13473篇
  2016年   13203篇
  2015年   7099篇
  2014年   10365篇
  2013年   27157篇
  2012年   22838篇
  2011年   32870篇
  2010年   21913篇
  2009年   21654篇
  2008年   29535篇
  2007年   32085篇
  2006年   21239篇
  2005年   23599篇
  2004年   19806篇
  2003年   18098篇
  2002年   16546篇
  2001年   17292篇
  2000年   13495篇
  1999年   10415篇
  1998年   9053篇
  1997年   8905篇
  1996年   8639篇
  1995年   7882篇
  1994年   7792篇
  1993年   7659篇
  1992年   8313篇
  1991年   8450篇
  1990年   8049篇
  1989年   7928篇
  1988年   8088篇
  1987年   7754篇
  1986年   7371篇
  1985年   10015篇
  1984年   10541篇
  1983年   8732篇
  1982年   9222篇
  1981年   9028篇
  1980年   8850篇
  1979年   8997篇
  1978年   9474篇
  1977年   9171篇
  1976年   9447篇
  1975年   8697篇
  1974年   8796篇
  1973年   9255篇
  1972年   6270篇
  1971年   5181篇
排序方式: 共有10000条查询结果,搜索用时 265 毫秒
21.
Journal of Optimization Theory and Applications - We consider a distributionally robust formulation of stochastic optimization problems arising in statistical learning, where robustness is with...  相似文献   
22.
Russian Journal of Applied Chemistry - In September 1975, the head of Russian electrochemists, Academician A.N. Frumkin (1895–1976), in his report at the XI Mendeleev Congress on General and...  相似文献   
23.
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   
24.
Makarov  G. N. 《JETP Letters》2022,115(11):660-666
JETP Letters - Using the spectroscopic data on the 235UF6 and 238UF6 molecules and on the lasing frequencies of CF4 and para-H2 lasers and recent results, a method has been proposed to increase the...  相似文献   
25.
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   
26.
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   
27.
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   
28.
Siberian Mathematical Journal - Let $ \{(A_{i},B_{i})\}_{i=1}^{m} $ be a set pair system. Füredi, Gyárfás, and Király called it $ 1 $ -cross intersecting if $...  相似文献   
29.
The recognition of boron compounds is well developed as boronic acids but untapped as organotrifluoroborate anions (R−BF3). We are exploring the development of these and other designer anions as anion-recognition motifs by considering them as substituted versions of the parent inorganic ion. To this end, we demonstrate strong and reliable binding of organic trifluoroborates, R−BF3, by cyanostar macrocycles that are size-complementary to the inorganic BF4 progenitors. We find that recognition is modulated by the substituent's sterics and that the affinities are retained using the common K+ salts of R−BF3 anions.  相似文献   
30.
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