全文获取类型
收费全文 | 800篇 |
免费 | 47篇 |
国内免费 | 99篇 |
专业分类
化学 | 40篇 |
力学 | 26篇 |
综合类 | 19篇 |
数学 | 726篇 |
物理学 | 135篇 |
出版年
2023年 | 12篇 |
2022年 | 5篇 |
2021年 | 14篇 |
2020年 | 11篇 |
2019年 | 17篇 |
2018年 | 15篇 |
2017年 | 18篇 |
2016年 | 20篇 |
2015年 | 19篇 |
2014年 | 34篇 |
2013年 | 85篇 |
2012年 | 27篇 |
2011年 | 30篇 |
2010年 | 49篇 |
2009年 | 59篇 |
2008年 | 44篇 |
2007年 | 52篇 |
2006年 | 53篇 |
2005年 | 53篇 |
2004年 | 37篇 |
2003年 | 42篇 |
2002年 | 48篇 |
2001年 | 39篇 |
2000年 | 32篇 |
1999年 | 24篇 |
1998年 | 26篇 |
1997年 | 23篇 |
1996年 | 14篇 |
1995年 | 9篇 |
1994年 | 5篇 |
1993年 | 3篇 |
1992年 | 1篇 |
1991年 | 2篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1988年 | 3篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 2篇 |
1984年 | 3篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1981年 | 2篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1978年 | 2篇 |
1977年 | 3篇 |
1973年 | 1篇 |
排序方式: 共有946条查询结果,搜索用时 15 毫秒
101.
S. Cafieri M. D’Apuzzo M. Marino A. Mucherino G. Toraldo 《Journal of Optimization Theory and Applications》2006,129(1):55-75
In this paper, we present an interior-point algorithm for large and sparse convex quadratic programming problems with bound
constraints. The algorithm is based on the potential reduction method and the use of iterative techniques to solve the linear
system arising at each iteration. The global convergence properties of the potential reduction method are reassessed in order
to take into account the inexact solution of the inner system. We describe the iterative solver, based on the conjugate gradient
method with a limited-memory incomplete Cholesky factorization as preconditioner. Furthermore, we discuss some adaptive strategies
for the fill-in and accuracy requirements that we use in solving the linear systems in order to avoid unnecessary inner iterations
when the iterates are far from the solution. Finally, we present the results of numerical experiments carried out to verify
the effectiveness of the proposed strategies. We consider randomly generated sparse problems without a special structure.
Also, we compare the proposed algorithm with the MOSEK solver.
Research partially supported by the MIUR FIRB Project RBNE01WBBB “Large-Scale Nonlinear Optimization.” 相似文献
102.
103.
In a previous work (Ref. 1), we examined some active set methods for the computation of the projection of a point onto a polyhedron when a feasible point is known. In this paper, we assume that such a point is not known and examine a method similar to the big-M method developed for the solution of linear programming problems. Special attention is given to the study of computing error propagation.This research was supported partially by the Progetto Finalizzato Informatica del CNR, Sottoprogetto P1, Sofmat. 相似文献
104.
Olof J. Staffans 《Transactions of the American Mathematical Society》1997,349(9):3679-3715
We consider the infinite horizon quadratic cost minimization problem for a stable time-invariant well-posed linear system in the sense of Salamon and Weiss, and show that it can be reduced to a spectral factorization problem in the control space. More precisely, we show that the optimal solution of the quadratic cost minimization problem is of static state feedback type if and only if a certain spectral factorization problem has a solution. If both the system and the spectral factor are regular, then the feedback operator can be expressed in terms of the Riccati operator, and the Riccati operator is a positive self-adjoint solution of an algebraic Riccati equation. This Riccati equation is similar to the usual algebraic Riccati equation, but one of its coefficients varies depending on the subspace in which the equation is posed. Similar results are true for unstable systems, as we have proved elsewhere.
105.
图的(g,f)-因子分解 总被引:1,自引:0,他引:1
设G是一个图,g(x)和f(x)是定义在图G的顶点集上的两个整数值函数且g≤f.图G的一个(g,f)-因子是G的一个支撑子图F使对任意的x∈V(F),有g(x)≤dF(x)≤f(x).如果图G的边集能划分为若干个边不相交的(g,f)-因子,则说图G是(g,f)-可因子化的.本文研究了图的(g,f)-可因子化的问题,给出了一个图G是(g,f)-可因子化的若干充分条件. 相似文献
106.
ACLASSOFFACTORIZATIONUPDATEALGORITHMFORSOLVINGSYSTEMSOFSPARSENONLINEAREQUATIONSBAIZHONGZHI(InstituteofComputationalMathematic... 相似文献
107.
We study the convergence rate of the distributions of normalized maximum likelihood estimators defined by a parametric family of discontinuous multidimensional densities in the case of a vector parameter. 相似文献
108.
在QCD因子化框架下 ,对可能的辐射湮灭衰变 B0s ,d→J/ψγ进行研究 .在标准模型中 ,相对于简单因子化下领头阶的分支比 ,αs 阶非因子化辐射修正对分支比有显著的量级上的改变 ,这些衰变可用来检验因子化方法 .在理论上 ,B介子稀有辐射衰变对超出标准模型的新物理特别敏感 .作为一个例子 ,我们考虑右手带电流对标准模型中左手流可能的混合效应 ,这个混合对衰变分支比有显著的影响 . 相似文献
109.
Heyman gives an interesting factorization of I-P, where P is the transition probability matrix for an ergodic Markov chain. We show that this factorization is valid if and only if
the Markov chain is recurrent. Moreover, we provide a decomposition result which includes all ergodic, null recurrent as well
as the transient Markov chains as special cases. Such a decomposition has been shown to be useful in the analysis of queues.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
110.
An Inexact Newton Method Derived from Efficiency Analysis 总被引:1,自引:0,他引:1
Naiyang?DengEmail author Yi?Xue Jianzhong?Zhang Ping?Zhong 《Journal of Global Optimization》2005,31(2):287-315
We consider solving an unconstrained optimization problem by Newton-PCG like methods in which the preconditioned conjugate gradient method is applied to solve the Newton equations. The main question to be investigated is how efficient Newton-PCG like methods can be from theoretical point of view. An algorithmic model with several parameters is established. Furthermore, a lower bound of the efficiency measure of the algorithmic model is derived as a function of the parameters. By maximizing this lower bound function, the parameters are specified and therefore an implementable algorithm is obtained. The efficiency of the implementable algorithm is compared with Newtons method by theoretical analysis and numerical experiments. The results show that this algorithm is competitive.Mathematics Subject Classification: 90C30, 65K05.This work was supported by the National Science Foundation of China Grant No. 10371131, and Hong Kong Competitive Earmarked Research Grant CityU 1066/00P from Hong Kong University Grant Council 相似文献