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   675篇
  免费   34篇
  国内免费   8篇
化学   348篇
晶体学   7篇
力学   17篇
数学   257篇
物理学   88篇
  2024年   1篇
  2023年   7篇
  2022年   30篇
  2021年   36篇
  2020年   33篇
  2019年   41篇
  2018年   34篇
  2017年   37篇
  2016年   42篇
  2015年   28篇
  2014年   33篇
  2013年   55篇
  2012年   36篇
  2011年   40篇
  2010年   31篇
  2009年   24篇
  2008年   32篇
  2007年   28篇
  2006年   17篇
  2005年   13篇
  2004年   17篇
  2003年   17篇
  2002年   17篇
  2001年   4篇
  2000年   5篇
  1999年   2篇
  1998年   2篇
  1997年   5篇
  1996年   2篇
  1994年   4篇
  1993年   1篇
  1992年   1篇
  1991年   3篇
  1989年   1篇
  1988年   3篇
  1987年   3篇
  1985年   3篇
  1982年   2篇
  1979年   1篇
  1978年   4篇
  1977年   4篇
  1976年   5篇
  1975年   2篇
  1974年   3篇
  1973年   5篇
  1971年   1篇
  1970年   1篇
  1968年   1篇
排序方式: 共有717条查询结果,搜索用时 15 毫秒
31.
The purpose of this note is to provide a -group whose mod-3 cohomology ring has a nilpotent element satisfying .

  相似文献   

32.
Anh  Pham Ky  Vinh  Nguyen The 《Numerical Algorithms》2019,81(3):983-1001
Numerical Algorithms - In this paper, we introduce a self-adaptive inertial gradient projection algorithm for solving monotone or strongly pseudomonotone variational inequalities in real Hilbert...  相似文献   
33.
Emissions from idle truck engines are a main source of pollution at container terminals. In this study, we focus on reducing such emission from waiting trucks as well as the related crane operations with a new truck arrival control method that gives individual truck limited time slots for entry. We develop a method to optimize the time slot assignment for individual trucks, aiming at minimizing total emissions from trucks and cranes at import yards. The method applies discrete event simulation to estimate total truck waiting times and crane moving distance, and then applies a genetic algorithm to minimize the generated emissions from these trucks and cranes. The experiment result shows that the truck arrivals should be controlled based on the stacking of import containers, and that such control is necessary for reducing truck idling emissions at a congested container terminal.  相似文献   
34.
Inspired by the great importance of equilibrium problems and the lexicographic order, we consider a parametric lexicographic equilibrium problem. Sufficient conditions for the upper semicontinuity, closedness, and continuity of solution maps are established. Many examples are provided to ensure the essentialness of the imposed assumptions. Applications to lexicographic variational inequalities and lexicographic optimization problems are discussed.  相似文献   
35.
Positivity - In the paper, we develop sum and chain rules of the generalized contingent derivative for set-valued mappings. Then, their applications to sensitivity analysis and optimality...  相似文献   
36.
In this paper, we establish some criteria for boundedness, stability properties, and separation of solutions of autonomous nonlinear nabla Riemann-Liouville scalar fractional difference equations. To derive these results, we prove the variation of constants formula for nabla Riemann-Liouville fractional difference equations.  相似文献   
37.
In this article, we introduce a class of Markov processes whose transition probability densities are defined by multifractional pseudodifferential evolution equations on compact domains with variable local dimension. The infinitesimal generators of these Markov processes are given by the trace of strongly elliptic pseudodifferential operators of variable order on such domains. The results derived provide a pseudomultifractal version of some existing special classes of multifractional Markov processes. In particular, pseudostable processes are defined on domains with variable local dimension in this framework. In the case where the local dimension of the domain and the local Hölder exponents of the transition probability densities are constant, the existing results on fractal versions of Lévy processes are recovered.  相似文献   
38.
In this paper, we introduce a splitting algorithm for solving equilibrium problems given by the difference of two bifunctions in a real Hilbert space. Under suitable assumptions on component bifunctions, we prove strong convergence of the proposed algorithm. In contrast to most existing projection-type methods for equilibrium problems, our algorithm does not require any convexity or monotonicity conditions on the resulting bifunction. Some numerical experiments and comparisons are given to illustrate the efficiency of the proposed algorithm.  相似文献   
39.
L. Q. Anh  N. V. Hung 《Positivity》2018,22(5):1223-1239
In this paper we consider strong bilevel vector equilibrium problems and introduce the concepts of Levitin–Polyak well-posedness and Levitin–Polyak well-posedness in the generalized sense for such problems. The notions of upper/lower semicontinuity involving variable cones for vector-valued mappings and their properties are proposed and studied. Using these generalized semicontinuity notions, we investigate sufficient and/or necessary conditions of the Levitin–Polyak well-posedness for the reference problems. Some metric characterizations of these Levitin–Polyak well-posedness concepts in the behavior of approximate solution sets are also discussed. As an application, we consider the special case of traffic network problems with equilibrium constraints.  相似文献   
40.
In this paper, we consider a wave equation with integral nonlocal boundary conditions of memory type. First, we establish two local existence theorems by using Faedo–Galerkin method and standard arguments of density. Next, we give a su?cient condition to guarantee the global existence and exponential decay of weak solutions. Finally, we present numerical results.  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