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   319篇
  免费   30篇
  国内免费   24篇
化学   1篇
力学   17篇
综合类   11篇
数学   337篇
物理学   7篇
  2024年   1篇
  2023年   4篇
  2021年   1篇
  2020年   7篇
  2019年   7篇
  2018年   11篇
  2017年   22篇
  2016年   19篇
  2015年   7篇
  2014年   12篇
  2013年   24篇
  2012年   9篇
  2011年   18篇
  2010年   13篇
  2009年   18篇
  2008年   16篇
  2007年   28篇
  2006年   19篇
  2005年   20篇
  2004年   21篇
  2003年   14篇
  2002年   10篇
  2001年   17篇
  2000年   7篇
  1999年   5篇
  1998年   11篇
  1997年   6篇
  1996年   7篇
  1995年   3篇
  1994年   2篇
  1992年   1篇
  1991年   2篇
  1990年   1篇
  1989年   1篇
  1988年   2篇
  1982年   1篇
  1980年   1篇
  1979年   1篇
  1978年   2篇
  1977年   2篇
排序方式: 共有373条查询结果,搜索用时 546 毫秒
41.
This paper is concerned with the asymptotic behavior analysis of solutions to a multidimensional wave equation. Assuming that there is no displacement term in the system and taking into consideration the presence of distributed or discrete time delay, we show that the solutions exponentially converge to their stationary state. The proof mainly consists in utilizing the resolvent method. The approach adopted in this work is also used to other physical systems.  相似文献   
42.
We consider the boundary value problems in a quarter-plane for a loaded heat conduction operator (one-dimensional in the space variable). A peculiarity of the operator in question is as follows: first, the spectral parameter is the coefficient of the loaded summand; second, the order of the derivative in the loaded summand is equal to that of the differential part of the operator, and third, the load point moves with a variable velocity. We demonstrate that the boundary value problem under study is Noetherian.  相似文献   
43.
We determine the spectrum and the resolvent operator of a drifted Laplace operator on a homogeneous tree, obtaining qualitatively different results according to the sign of the drift in the direction of a boundary point.

  相似文献   

44.
IIntroductlonLet fi be a bounded open set In the n-dimensional Euclldean space R”withtheboundaryo0.In this paper,we shallessentiallydeal with thefollowingeigenvalue problem:,nD 一)。o…4km)螂川川J”人川川,x〔u,丸 人k=1\“’“)llillj=U.U b UI[。where丸 meanso/axj,and we suPPose that coeaclents aj。(x),J;k= 1,2;…,。satisfy the following conditions:(1)aj。(x)is real function and belong to Cm(R”);(2)There exists an M>0;such that Iajk(x)l<M;;;k二 1,2,…,n;148 Ann ofDiff Eqs Vol…  相似文献   
45.
设K∈C(R+)和B是一个有界线性算子.作者证明如果犃生成一个指数有界的A正则预解算子族,那么BA,AB或A(I+B),(I+B)A也生成一个指数有界的k-正则预解算子族.此外,作者也给出了k正则预解算子族的加法扰动的相应结果.  相似文献   
46.
LetE be a Hausdorff topological space and let β(E) be its Borel σ-field. Letm be a σ-finite measure on (E, β(E)). A necessary and sufficient condition for a Markov resolvent onL P (E,m) to be associated with anm-tightm-special standard process (with state spaceE) is given. Furthermore some new examples which do not belong to the framework of Dirichlet space are also given. Project supported by the Youth Foundation of Chinese Academy of Sciences.  相似文献   
47.
We present the structure of the resolvent of a difference kernel, which allows us to study the asymptotic behavior of the solution of the renewal equation for a given asymptotic behavior of the constant term. An asymptotic representation for the resolvent is obtained under minimal requirements on the moments of the kernel. Similar results are given for integro-differential equations. Translated fromMatematicheskie Zametki, Vol. 62, No. 1, pp. 88–94, July, 1997. Translated by M. A. Shishkova  相似文献   
48.
Savchenko  S. V. 《Mathematical Notes》2003,74(3-4):557-568
We show that under perturbations by a rank-one typical operator, a fixed eigenvalue loses one Jordan block of maximal order, while the orders of the other Jordan blocks remain unchanged. We construct the first-order perturbation theory for the new eigenvalues and the zero-order approximations to the corresponding eigenvectors.  相似文献   
49.
A Markov chain (with a discrete state space and a continuous parameter) is perturbed by forcing a chain to return to “permissible” states whenever it happens to enter “forbidden” states, with returns governed by a replacement distribution.The compensation method is employed to obtain the distribution for the modified chain, in terms of the original chain and the perturbation mechanism.Emphasis is placed on ergodic chains, and interpretation of results in terms of perturbation theory of semi-groups and the ergodic potential theory (based on the fundamental matrix of a chain) is mentioned.  相似文献   
50.
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