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   552029篇
  免费   5741篇
  国内免费   1169篇
化学   277629篇
晶体学   7892篇
力学   26639篇
综合类   6篇
数学   77044篇
物理学   169729篇
  2021年   4744篇
  2020年   5437篇
  2019年   6392篇
  2018年   8969篇
  2017年   8991篇
  2016年   12647篇
  2015年   7142篇
  2014年   11344篇
  2013年   24923篇
  2012年   19764篇
  2011年   22941篇
  2010年   17193篇
  2009年   16965篇
  2008年   21298篇
  2007年   21106篇
  2006年   19119篇
  2005年   17252篇
  2004年   15998篇
  2003年   14429篇
  2002年   14405篇
  2001年   14601篇
  2000年   11548篇
  1999年   8774篇
  1998年   7800篇
  1997年   7650篇
  1996年   7232篇
  1995年   6472篇
  1994年   6506篇
  1993年   6493篇
  1992年   6809篇
  1991年   7078篇
  1990年   6965篇
  1989年   6847篇
  1988年   6657篇
  1987年   6600篇
  1986年   6183篇
  1985年   7864篇
  1984年   8203篇
  1983年   6856篇
  1982年   7361篇
  1981年   6956篇
  1980年   6608篇
  1979年   7077篇
  1978年   7348篇
  1977年   7340篇
  1976年   7634篇
  1975年   6906篇
  1974年   6926篇
  1973年   7368篇
  1972年   5382篇
排序方式: 共有10000条查询结果,搜索用时 78 毫秒
21.
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   
22.
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   
23.
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   
24.
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   
25.
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   
26.

A kinetic study of the effect of thermoheliox (inhalation of a helium and oxygen mixture, 70 °C) on the functional hemodynamics of the human brain by functional magnetic resonance imaging was carried out. The dynamic responses of the BOLD signal were found to be biphasic. An empirical equation describing the first phase of the hemodynamic response to visual stimulus was proposed. It was shown that preliminary inhalation of thermoheliox stimulates the hemodynamic responses by slowing down the vasoconstriction.

  相似文献   
27.
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   
28.
Russian Physics Journal - The temperature dependences of the linear dielectric permittivity ε′ and the third harmonic coefficient γ3ω for nanocomposites obtained by embedding a...  相似文献   
29.
Central European Journal of Operations Research - Sustainability practice within supply chains remains in an early development phase. Enterprises still need tools that support the integration of...  相似文献   
30.
Journal of Applied Mechanics and Technical Physics - Implicit finite-volume predictor-corrector algorithms based on the splitting method are proposed for the numerical solution of the...  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