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   1453536篇
  免费   30152篇
  国内免费   7800篇
化学   743824篇
晶体学   20654篇
力学   77084篇
综合类   107篇
数学   252679篇
物理学   397140篇
  2021年   13772篇
  2020年   16189篇
  2019年   16463篇
  2018年   14685篇
  2016年   29465篇
  2015年   21663篇
  2014年   31248篇
  2013年   76179篇
  2012年   45117篇
  2011年   45780篇
  2010年   40587篇
  2009年   41835篇
  2008年   43224篇
  2007年   39923篇
  2006年   44099篇
  2005年   36934篇
  2004年   36740篇
  2003年   33680篇
  2002年   34088篇
  2001年   33672篇
  2000年   28171篇
  1999年   24192篇
  1998年   21800篇
  1997年   21684篇
  1996年   21658篇
  1995年   19596篇
  1994年   19052篇
  1993年   18661篇
  1992年   19143篇
  1991年   19301篇
  1990年   18393篇
  1989年   18382篇
  1988年   17961篇
  1987年   17789篇
  1986年   16783篇
  1985年   23249篇
  1984年   24293篇
  1983年   20323篇
  1982年   22024篇
  1981年   21173篇
  1980年   20510篇
  1979年   20872篇
  1978年   22065篇
  1977年   21668篇
  1976年   21508篇
  1975年   20223篇
  1974年   19948篇
  1973年   20410篇
  1972年   14806篇
  1967年   12921篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
81.
We prove a well-posedness result for two pseudo-parabolic problems, which can be seen as two models for the same electrical conduction phenomenon in heterogeneous media, neglecting the magnetic field. One of the problems is the concentration limit of the other one, when the thickness of the dielectric inclusions goes to zero. The concentrated problem involves a transmission condition through interfaces, which is mediated by a suitable Laplace-Beltrami type equation.  相似文献   
82.
Kobayashi  M.  Zhang  Y.  Ishikawa  H.  Sun  J.  Oddershede  J.  Juul Jensen  D.  Miura  H. 《Experimental Mechanics》2021,61(5):817-828
Experimental Mechanics - The internal strain distribution developing during plastic deformation is important for understanding the mechanical properties of polycrystalline materials. Such...  相似文献   
83.
84.
Physics of Atomic Nuclei - The muon puzzle is an excess of muon bundles generated by primary cosmic rays (PCR) at energies above 10 $${}^{17}$$ eV compared to estimations that assume even a heavy...  相似文献   
85.
Taherian  A.  Toutounian  F. 《Numerical Algorithms》2021,88(4):1831-1850
Numerical Algorithms - In this paper, the block generalized product-type bi-conjugate gradient (GPBi-CG) method for solving large, sparse nonsymmetric linear systems of equations with multiple...  相似文献   
86.
Shavgulidze  N. E. 《Mathematical Notes》2021,110(1-2):297-300
Mathematical Notes -  相似文献   
87.

In this paper, we design a Branch and Bound algorithm based on interval arithmetic to address nonconvex robust optimization problems. This algorithm provides the exact global solution of such difficult problems arising in many real life applications. A code was developed in MatLab and was used to solve some robust nonconvex problems with few variables. This first numerical study shows the interest of this approach providing the global solution of such difficult robust nonconvex optimization problems.

  相似文献   
88.
89.
A formal computation proving a new operator identity from known ones is, in principle, restricted by domains and codomains of linear operators involved, since not any two operators can be added or composed. Algebraically, identities can be modelled by noncommutative polynomials and such a formal computation proves that the polynomial corresponding to the new identity lies in the ideal generated by the polynomials corresponding to the known identities. In order to prove an operator identity, however, just proving membership of the polynomial in the ideal is not enough, since the ring of noncommutative polynomials ignores domains and codomains. We show that it suffices to additionally verify compatibility of this polynomial and of the generators of the ideal with the labelled quiver that encodes which polynomials can be realized as linear operators. Then, for every consistent representation of such a quiver in a linear category, there exists a computation in the category that proves the corresponding instance of the identity. Moreover, by assigning the same label to several edges of the quiver, the algebraic framework developed allows to model different versions of an operator by the same indeterminate in the noncommutative polynomials.  相似文献   
90.
Crystallography Reports - The crystal and molecular structures of Cl–C6H4–O–C16H33 (I) have been studied, and its differential scanning calorimetry (DSC) study is performed....  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