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   2544篇
  免费   368篇
  国内免费   309篇
化学   316篇
晶体学   14篇
力学   131篇
综合类   82篇
数学   2078篇
物理学   600篇
  2024年   3篇
  2023年   37篇
  2022年   33篇
  2021年   50篇
  2020年   81篇
  2019年   65篇
  2018年   100篇
  2017年   104篇
  2016年   105篇
  2015年   81篇
  2014年   115篇
  2013年   188篇
  2012年   133篇
  2011年   123篇
  2010年   111篇
  2009年   123篇
  2008年   154篇
  2007年   154篇
  2006年   139篇
  2005年   141篇
  2004年   117篇
  2003年   129篇
  2002年   126篇
  2001年   132篇
  2000年   111篇
  1999年   86篇
  1998年   62篇
  1997年   53篇
  1996年   72篇
  1995年   34篇
  1994年   29篇
  1993年   17篇
  1992年   17篇
  1991年   22篇
  1990年   16篇
  1989年   8篇
  1988年   18篇
  1987年   16篇
  1986年   11篇
  1985年   15篇
  1984年   10篇
  1983年   11篇
  1982年   9篇
  1981年   5篇
  1980年   9篇
  1979年   8篇
  1978年   11篇
  1977年   6篇
  1976年   9篇
  1974年   4篇
排序方式: 共有3221条查询结果,搜索用时 15 毫秒
121.
Asymptotic normality of the solutions of the initial-value problems for multidimensional Burgers' equation with weakly dependent possible non-Gaussian initial condition is proved.  相似文献   
122.
The superconducting and magnetic properties of Nb/Pd1-xFex/Nb triple layers with constant Nb layer thickness dNb=200 ? and different interlayer thicknesses 3 ?≤ dPdFe ≤ ? are investigated. The thickness dependence of the magnetization and of the superconducting transition temperature shows that for small iron concentration x the Pd1-xFex layer is likely to be in the paramagnetic state for very thin films whereas ferromagnetic order is established for x ≥ 0.13. The parallel critical field Bc2||(T){B_{c2||}}(T) exhibits a transition from two-dimensional (2D) behavior where the Nb films are coupled across the interlayer, towards a 2D behavior of decoupled Nb films with increasing dPdFeand/or x. This transition allows a determination of the penetration depth xF{\xi _F} of Cooper pairs into the Pd1-xFex layer as a function of x. For samples with a ferromagnetic interlayer xF{\xi _F} is found to be independent of x.  相似文献   
123.
The role of hypernuclear physics for the physics of neutron stars is delineated. Hypernuclear potentials in dense matter control the hyperon composition of dense neutron star matter. The three-body interactions of nucleons and hyperons determine the stiffness of the neutron star equation of state and thereby the maximum neutron star mass. Two-body hyperon–nucleon and hyperon–hyperon interactions give rise to hyperon pairing which exponentially suppresses cooling of neutron stars via the direct hyperon URCA processes. Nonmesonic weak reactions with hyperons in dense neutron star matter govern the gravitational wave emissions due to the r-mode instability of rotating neutron stars.  相似文献   
124.
We have been puzzled by the involvement of weak organic and inorganic bases in the synthesis of metal–N-heterocyclic carbene (NHC) complexes. Such bases are insufficiently strong to permit the presumed required deprotonation of the azolium salt (the carbene precursor) prior to metal binding. Experimental and computational studies provide support for a base-assisted concerted process that does not require free NHC formation. The synthetic protocol was found applicable to a number of transition-metal- and main-group-centered NHC compounds and could become the synthetic route of choice to form M–NHC bonds.  相似文献   
125.
In the multidimensional case, second-order weak Runge-Kutta methods for stochastic differential equation (SDE) need simulation of correlated random variables, unless the diffusion matrix of SDE satisfies the commutativity condition. In this paper, we show that this can be avoided for some types of diffusion matrices and test functions important for applications. Published in Lietuvos Matematikos Rinkinys, Vol. 46, No. 3, pp. 403–412, July–September, 2006.  相似文献   
126.
In this article, approximate solutions of multi-objective optimization problems are analysed. The notion of approximate solution suggested by Kutateladze is dealt with, and, utilizing different scalarization approaches, some necessary and sufficient conditions for ?-(strong, weak, proper) efficiency are provided. Almost all of the provided results are established without any convexity assumption.  相似文献   
127.
128.
129.
在本文中,我们通过引入一类Frechet空间,得到了三维有界光滑区域上的地磁流方程的弱解的整体吸引子的存在性。  相似文献   
130.
We prove that a uniform, rooted unordered binary tree (also known as rooted, binary Pólya tree) with n leaves has the Brownian continuum random tree as its scaling limit for the Gromov‐Hausdorff topology. The limit is thus, up to a constant factor, the same as that of uniform plane trees or labeled trees. Our analysis rests on a combinatorial and probabilistic study of appropriate trimming procedures of trees. © 2011 Wiley Periodicals, Inc. Random Struct. Alg., 38, 467–501, 2011  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