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   1359985篇
  免费   30474篇
  国内免费   8461篇
化学   685067篇
晶体学   20418篇
力学   75081篇
综合类   172篇
数学   242539篇
物理学   375643篇
  2021年   13545篇
  2020年   16039篇
  2019年   16135篇
  2018年   12962篇
  2016年   28157篇
  2015年   20989篇
  2014年   30606篇
  2013年   74711篇
  2012年   39282篇
  2011年   36760篇
  2010年   37923篇
  2009年   40236篇
  2008年   35969篇
  2007年   31796篇
  2006年   37451篇
  2005年   30364篇
  2004年   30905篇
  2003年   29010篇
  2002年   29961篇
  2001年   29890篇
  2000年   25719篇
  1999年   22938篇
  1998年   21135篇
  1997年   21122篇
  1996年   21193篇
  1995年   19239篇
  1994年   18711篇
  1993年   18229篇
  1992年   18524篇
  1991年   18711篇
  1990年   17894篇
  1989年   17922篇
  1988年   17527篇
  1987年   17500篇
  1986年   16445篇
  1985年   22872篇
  1984年   23988篇
  1983年   20102篇
  1982年   21731篇
  1981年   20898篇
  1980年   20282篇
  1979年   20592篇
  1978年   21774篇
  1977年   21465篇
  1976年   21211篇
  1975年   19855篇
  1974年   19518篇
  1973年   19936篇
  1972年   14472篇
  1967年   12708篇
排序方式: 共有10000条查询结果,搜索用时 609 毫秒
111.
Doklady Physics - This work is devoted to analysis and generalization of the kinetic criteria of vitrification using the model of delocalized atoms. The generalized criterion of a...  相似文献   
112.
Russian Physics Journal - A unified equation for the pressure drop in the apparatus with the stationary and fluidized granular layers is derived. The resulting recurrent equation is used to...  相似文献   
113.
Faul  Peter F. 《Semigroup Forum》2021,102(3):655-673
Semigroup Forum - It is well known that the set of isomorphism classes of extensions of groups with abelian kernel is characterized by the second cohomology group. In this paper we generalise this...  相似文献   
114.
Kumar  Sanjay  Jiwari  Ram  Mittal  R. C.  Awrejcewicz  Jan 《Nonlinear dynamics》2021,104(1):661-682
Nonlinear Dynamics - In this article, the authors simulate and study dark and bright soliton solutions of 1D and 2D regularized long wave (RLW) models. The RLW model occurred in various fields such...  相似文献   
115.
Mejjaoli  H.  Ben Saïd  S. 《Analysis Mathematica》2021,47(3):629-663
Analysis Mathematica - We introduce and study the k-Hankel Gabor transform. We investigate the localization operators for this transform. In particular, we study their trace class properties and we...  相似文献   
116.
A numerical model was developed and validated to investigate the fluid–structure interactions between fully developed pipe flow and core–shell-structured microcapsule in a microchannel. Different flow rates and microcapsule shell thicknesses were considered. A sixth-order rotational symmetric distribution of von Mises stress over the microcapsule shell can be observed on the microcapsule with a thinner shell configuration, especially at higher flow rate conditions. It is also observed that when being carried along in a fully developed pipe flow, the microcapsule with a thinner shell tends to accumulate stress at a higher rate compared to that with a thicker shell. In general, for the same microcapsule configuration, higher flow velocity would induce a higher stress level over the microcapsule shell. The deformation gradient was used to capture the microcapsule's deformation in the present study. The effect of Young's modulus on the microcapsule shell on the microcapsule deformation was investigated as well. Our findings will shed light on the understanding of the stability of core–shell-structured microcapsule when subjected to flow-induced shear stress in a microfluidic system, enabling a more exquisite control over the breakup dynamics of drug-loaded microcapsule for biomedical applications.  相似文献   
117.
Chen  C. Y.  Kao  C. L.  Huang  S. T.  Kuo  C. E.  Song  P. L.  Li  W. J.  Hsu  L. T.  Li  H. T. 《Chemistry of Natural Compounds》2022,58(1):107-109
Chemistry of Natural Compounds -  相似文献   
118.
Pentafluorosulfanyl (SF5)-containing compounds and corresponding analogs are a highly valuable class of fluorine-containing building blocks owing to their unique properties. The reason for that is the set of peculiar and tremendously beneficial characteristics they can impart on molecules once introduced onto them. Despite this, their application in distinct scientific fields remains modest, given the extremely harsh reaction conditions needed to access such compounds. The recent synthetic approaches via S−F, and C−SF5 bond formation as well as the use of SF5-containing building blocks embody a “stairway-to-heaven” loophole in the synthesis of otherwise-inaccessible chemical scaffolds only a few years ago. Herein, we report and evaluate the properties of the SF5 group and analogs, by summarizing synthetic methodologies available to access them as well as following applications in material science and medicinal chemistry since 2015.  相似文献   
119.
Russian Physics Journal - The process of radiative decay of a Higgs boson into a fermion-antifermion pair $$ H\Rightarrow \overline{ff}\upgamma . $$ is investigated within the framework of the...  相似文献   
120.
Filippov  A. N. 《Colloid Journal》2022,84(3):332-343
Colloid Journal - The capillary-osmosis and reverse-osmosis coefficients of an ion-exchange membrane have been calculated as the kinetic coefficients of the Onsager matrix within the thermodynamics...  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