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   9088篇
  免费   733篇
  国内免费   488篇
化学   1254篇
晶体学   145篇
力学   708篇
综合类   72篇
数学   6573篇
物理学   1557篇
  2024年   20篇
  2023年   76篇
  2022年   110篇
  2021年   117篇
  2020年   238篇
  2019年   237篇
  2018年   241篇
  2017年   253篇
  2016年   262篇
  2015年   215篇
  2014年   386篇
  2013年   856篇
  2012年   329篇
  2011年   503篇
  2010年   504篇
  2009年   571篇
  2008年   634篇
  2007年   575篇
  2006年   498篇
  2005年   454篇
  2004年   394篇
  2003年   355篇
  2002年   322篇
  2001年   253篇
  2000年   210篇
  1999年   211篇
  1998年   165篇
  1997年   162篇
  1996年   143篇
  1995年   109篇
  1994年   99篇
  1993年   78篇
  1992年   66篇
  1991年   53篇
  1990年   48篇
  1989年   33篇
  1988年   41篇
  1987年   24篇
  1986年   43篇
  1985年   46篇
  1984年   55篇
  1983年   40篇
  1982年   50篇
  1981年   42篇
  1980年   38篇
  1979年   45篇
  1978年   30篇
  1977年   17篇
  1976年   20篇
  1973年   12篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
一类泛函微分方程周期解的存在性与应用   总被引:6,自引:1,他引:5  
本文给出了一类滞后型泛函微分方程有一个周期解的四个充分性定理,其结果明显地优于著名的Yoshizawa周期解定理,最后给出了应用实例。  相似文献   
72.
This paper is devoted to the convergence of solutions of the compressible Euler equations towards solutions of the pressureless gas dynamics system, when the pressure tends to 0. The goal is to prove accurate uniform bounds for particular solutions of the Euler equations.

  相似文献   

73.
关于一类空间齐次推广的耗散碰撞Boltzmann方程Cauchy问题 ,对于一般的初始条件得到了正古典解的存在唯一性 .  相似文献   
74.
We consider the Schrödinger–Poisson system in the repulsive (plasma physics) Coulomb case. Given a stationary state from a certain class we prove its nonlinear stability, using an appropriately defined energy-Casimir functional as Lyapunov function. To obtain such states we start with a given Casimir functional and construct a new functional which is in some sense dual to the corresponding energy-Casimir functional. This dual functional has a unique maximizer which is a stationary state of the Schrödinger–Poisson system and lies in the stability class. The stationary states are parameterized by the equation of state, giving the occupation probabilities of the quantum states as a strictly decreasing function of their energy levels.  相似文献   
75.
Partial critical dependences of the form current-magnetic field in a two-layered symmetric Josephson junction are modeled. A numerical experiment shows that, for the zero interaction coefficient between the layers of the junction, jumps of the critical currents corresponding to different distributions of the magnetic fluxes in the layers may appear on the critical curves. This fact allows a mathematical interpretation of the results of some recent experimental results for two-layered junctions as a consequence of discontinuities of partial critical curves.  相似文献   
76.
This paper is concerned with the existence of positive solutions of two-point Dirichlet singular and nonsingular boundary problems for second-order quasi-linear differential equations with changing sign nonlinearities.  相似文献   
77.
This article will combine the finite element method, the interpolated coefftcient finite element method, the eigenfunction expansion method, and the search-extension method to obtain the multiple solutions for semilinear elliptic equations. This strategy not only grently reduces the expensive computation, but also is successfully implemented to obtain multiple solutions for a class of semilinear elliptic boundary value problems with non-odd nonlinearity on some convex or nonconvex domains. Numerical solutions illustrated by their graphics for visualization will show the efficiency of the approach.  相似文献   
78.
关于非线性Schrodinger方程混合问题解的破裂和质量集中   总被引:1,自引:0,他引:1  
秦玉明 《应用数学》1996,9(2):185-192
本文讨论了一类非线性Schrodinger方程混合问题解的破裂现象,blow-up时刻的估计和质量集中定理,并推广和改进了[l~3]中的结果.  相似文献   
79.
This paper describes a numerical realization of an extended continuous Newton method defined by Diener. It traces a connected set of locally one-dimensional trajectories which contains all critical points of a smooth functionf: n . The results show that the method is effectively applicable.The authors would like to thank L. C. W. Dixon for pointing out some errors in the original version of this paper and for several suggestions of improvements.  相似文献   
80.
We consider the Stackelberg problem corresponding to a two-player game in which one of the two players has the leadership in playing the game. We present a general approach for approximating the considered hierarchical programming problem by a sequence of two-level optimization problems. From a practical point of view, we also give some results for asymptotically Stackelberg approximating sequences and for problems with perturbed constraints.This paper is based upon results first presented at Journées Fermat: Mathematics for Optimization, Toulouse, France, May 1985.  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