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   2128篇
  免费   144篇
  国内免费   295篇
化学   25篇
力学   79篇
综合类   70篇
数学   2308篇
物理学   85篇
  2024年   2篇
  2023年   17篇
  2022年   27篇
  2021年   19篇
  2020年   49篇
  2019年   48篇
  2018年   55篇
  2017年   68篇
  2016年   72篇
  2015年   34篇
  2014年   67篇
  2013年   154篇
  2012年   101篇
  2011年   105篇
  2010年   110篇
  2009年   135篇
  2008年   153篇
  2007年   146篇
  2006年   130篇
  2005年   127篇
  2004年   75篇
  2003年   136篇
  2002年   101篇
  2001年   83篇
  2000年   82篇
  1999年   90篇
  1998年   56篇
  1997年   60篇
  1996年   44篇
  1995年   30篇
  1994年   26篇
  1993年   18篇
  1992年   21篇
  1991年   14篇
  1990年   11篇
  1989年   8篇
  1988年   5篇
  1987年   3篇
  1986年   8篇
  1985年   6篇
  1984年   10篇
  1983年   8篇
  1982年   11篇
  1981年   12篇
  1980年   5篇
  1979年   9篇
  1978年   5篇
  1977年   8篇
  1973年   3篇
排序方式: 共有2567条查询结果,搜索用时 15 毫秒
171.
给出了nZ的全部理想、极大理想和素理想,并研究了nZ的商环的构造以及为域的条件,解决了Z<,n>的子域的存在和个数问题.  相似文献   
172.
We present a refinement ofthe bounded modified realizability which provides both upper and lower bounds for witnesses. Our interpretation is based on a generalisation of Howard/Bezem's notion of strong majorizability. We show how the bounded modified realizability coincides with (a weak version of) our interpretation in the case when least elements exist (e.g. natural numbers). The new interpretation, however, permits the extraction of more accurate bounds, and provides an ideal setting for dealing directly with data types whose natural ordering is not well‐founded (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)  相似文献   
173.
In this paper, we focus on a useful modification of the decomposition method by He et al. (Ref. 1). Experience on applications has shown that the number of iterations of the original method depends significantly on the penalty parameter. The main contribution of our method is that we allow the penalty parameter to vary automatically according to some self-adaptive rules. As our numerical simulations indicate, the modified method is more flexible and efficient in practice. A detailed convergence analysis of our method is also included.  相似文献   
174.
This article studies some Bolza-type problems governed by second-order differential inclusions with two boundary conditions, where the controls are Young measures.  相似文献   
175.
The aim of the paper is to propose an iterative regularization method of proximal point type for finding a common solution for a finite family of inverse-strongly monotone equations in Hilbert spaces.  相似文献   
176.
We propose a modification of the classical extragradient and proximal point algorithms for finding a zero of a maximal monotone operator in a Hilbert space. At each iteration of the method, an approximate extragradient-type step is performed using information obtained from an approximate solution of a proximal point subproblem. The algorithm is of a hybrid type, as it combines steps of the extragradient and proximal methods. Furthermore, the algorithm uses elements in the enlargement (proposed by Burachik, Iusem and Svaiter) of the operator defining the problem. One of the important features of our approach is that it allows significant relaxation of tolerance requirements imposed on the solution of proximal point subproblems. This yields a more practical proximal-algorithm-based framework. Weak global convergence and local linear rate of convergence are established under suitable assumptions. It is further demonstrated that the modified forward-backward splitting algorithm of Tseng falls within the presented general framework.  相似文献   
177.
Classes of Runge–Kutta methods preserving the monotonicity of ordinary and delay differential equations are identified. Essentially, the vector b and the matrix A from the Butcher tableau should be such that all components of b are positive and all components of the matrix B(r)A, where B(r) is the inverse of the matrix I+rA, are nonnegative for sufficiently small positive r. The latter is satisfied by all explicit, diagonally-implicit and fully implicit Runge–Kutta methods for which all of the components of the matrix A, except those that are zero by definition, are positive.  相似文献   
178.
讨论向量值函数的Banach代数L∞(T;X)的极大理想空间的拓扑性质和代数性质,得到了若干结果;给出了Banach空间H∞(D;X)中闭单位球的端点的一条性质.  相似文献   
179.
Applying simulated annealing to location-planning models   总被引:9,自引:0,他引:9  
Simulated annealing is a computational approach that simulates an annealing schedule used in producing glass and metals. Originally developed by Metropolis et al. in 1953, it has since been applied to a number of integer programming problems, including the p-median location-allocation problem. However, previously reported results by Golden and Skiscim in 1986 were less than encouraging. This article addresses the design of a simulated-annealing approach for the p-median and maximal covering location problems. This design has produced very good solutions in modest amounts of computer time. Comparisons with an interchange heuristic demonstrate that simulated annealing has potential as a solution technique for solving location-planning problems and further research should be encouraged.  相似文献   
180.
苏简兵  殷慰萍 《数学学报》2007,50(4):881-886
本文讨论两种类型的极值问题,其中一种类型的极值问题可以认为是复平面上经典的Schwarz引理在高维的一个推广;另一种类型的极值是某空间上的度量,可以用来考虑域的双全纯等价分类问题.在本文中,k<1时Cartan-Hartogs域与单位超球间的极值与极值映照被得到。  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