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   272098篇
  免费   2499篇
  国内免费   645篇
化学   144848篇
晶体学   4219篇
力学   12138篇
综合类   9篇
数学   30101篇
物理学   83927篇
  2019年   2346篇
  2018年   3165篇
  2017年   3146篇
  2016年   4588篇
  2015年   2757篇
  2014年   4374篇
  2013年   10949篇
  2012年   8291篇
  2011年   10166篇
  2010年   7240篇
  2009年   7005篇
  2008年   9507篇
  2007年   9717篇
  2006年   9111篇
  2005年   8268篇
  2004年   7602篇
  2003年   6873篇
  2002年   6800篇
  2001年   7412篇
  2000年   5733篇
  1999年   4411篇
  1998年   3902篇
  1997年   3902篇
  1996年   3670篇
  1995年   3400篇
  1994年   3575篇
  1993年   3288篇
  1992年   3739篇
  1991年   3720篇
  1990年   3652篇
  1989年   3520篇
  1988年   3621篇
  1987年   3510篇
  1986年   3335篇
  1985年   4432篇
  1984年   4709篇
  1983年   3935篇
  1982年   4068篇
  1981年   3990篇
  1980年   3966篇
  1979年   3931篇
  1978年   4243篇
  1977年   4171篇
  1976年   4222篇
  1975年   3903篇
  1974年   3942篇
  1973年   4096篇
  1972年   2876篇
  1971年   2399篇
  1970年   2189篇
排序方式: 共有10000条查询结果,搜索用时 109 毫秒
11.
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   
12.
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   
13.
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   
14.
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   
15.
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   
16.
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   
17.
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   
18.
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   
19.
20.
Russian Physics Journal - The specific features of the sorption activity of silver nanoparticles (AgNPs) on biodegradable polymers of natural (collagen) and artificial (polyamide 6.6) origin have...  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