全文获取类型
收费全文 | 9832篇 |
免费 | 554篇 |
国内免费 | 42篇 |
专业分类
化学 | 7320篇 |
晶体学 | 33篇 |
力学 | 159篇 |
数学 | 1515篇 |
物理学 | 1401篇 |
出版年
2023年 | 75篇 |
2022年 | 95篇 |
2021年 | 154篇 |
2020年 | 231篇 |
2019年 | 200篇 |
2018年 | 146篇 |
2017年 | 120篇 |
2016年 | 416篇 |
2015年 | 379篇 |
2014年 | 403篇 |
2013年 | 489篇 |
2012年 | 663篇 |
2011年 | 707篇 |
2010年 | 503篇 |
2009年 | 413篇 |
2008年 | 652篇 |
2007年 | 579篇 |
2006年 | 542篇 |
2005年 | 556篇 |
2004年 | 472篇 |
2003年 | 340篇 |
2002年 | 313篇 |
2001年 | 158篇 |
2000年 | 129篇 |
1999年 | 150篇 |
1998年 | 117篇 |
1997年 | 161篇 |
1996年 | 114篇 |
1995年 | 109篇 |
1994年 | 108篇 |
1993年 | 92篇 |
1992年 | 91篇 |
1991年 | 62篇 |
1990年 | 43篇 |
1989年 | 71篇 |
1988年 | 57篇 |
1987年 | 32篇 |
1986年 | 31篇 |
1985年 | 48篇 |
1984年 | 38篇 |
1983年 | 24篇 |
1982年 | 46篇 |
1981年 | 32篇 |
1980年 | 27篇 |
1979年 | 24篇 |
1978年 | 24篇 |
1977年 | 21篇 |
1975年 | 23篇 |
1973年 | 16篇 |
1968年 | 15篇 |
排序方式: 共有10000条查询结果,搜索用时 156 毫秒
991.
992.
993.
An interior-point affine-scaling trust-region method for semismooth equations with box constraints 总被引:1,自引:0,他引:1
An algorithm for the solution of a semismooth system of equations with box constraints is described. The method is an affine-scaling
trust-region method. All iterates generated by this method are strictly feasible. In this way, possible domain violations
outside or on the boundary of the box are avoided. The method is shown to have strong global and local convergence properties
under suitable assumptions, in particular, when the method is used with a special scaling matrix. Numerical results are presented
for a number of problems arising from different areas. 相似文献
994.
Dmitri V. Alekseevsky Andreas Kriegl Mark Losik Peter W. Michor 《Annali di Matematica Pura ed Applicata》2007,186(1):25-58
We investigate discrete groups G of isometries of a complete connected Riemannian manifold M which are generated by reflections, in particular those generated by disecting reflections. We show that these are Coxeter
groups, and that the orbit space M/G is isometric to a Weyl chamber C which is a Riemannian manifold with corners and certain angle conditions along intersections of faces. We can also reconstruct
the manifold and its action from the Riemannian chamber and its equipment of isotropy group data along the faces. We also
discuss these results from the point of view of Riemannian orbifolds.
Mathematics Subject Classification Primary 51F15, 53C20, 20F55, 22E40 相似文献
995.
Stochastic programming is recognized as a powerful tool to help decision making under uncertainty in financial planning. The deterministic equivalent formulations of these stochastic programs have huge dimensions even for moderate numbers of assets, time stages and scenarios per time stage. So far models treated by mathematical programming approaches have been limited to simple linear or quadratic models due to the inability of currently available solvers to solve NLP problems of typical sizes. However stochastic programming problems are highly structured. The key to the efficient solution of such problems is therefore the ability to exploit their structure. Interior point methods are well-suited to the solution of very large non-linear optimization problems. In this paper we exploit this feature and show how portfolio optimization problems with sizes measured in millions of constraints and decision variables, featuring constraints on semi-variance, skewness or non-linear utility functions in the objective, can be solved with the state-of-the-art solver. 相似文献
996.
997.
We investigate the derived structures of compact polygons at half-regular and at regular points. This enables us to give a geometric characterization of the real or complex split Cayley hexagon. 相似文献
998.
Andreas Fischer 《Mathematical Programming》2002,94(1):91-124
An iterative framework for solving generalized equations with nonisolated solutions is presented. For generalized equations
with the structure , where is a multifunction and F is single-valued, the framework covers methods that, at each step, solve subproblems of the type . The multifunction approximates F around s. Besides a condition on the quality of this approximation, two other basic assumptions are employed to show Q-superlinear
or Q-quadratic convergence of the iterates to a solution. A key assumption is the upper Lipschitz-continuity of the solution
set map of the perturbed generalized equation . Moreover, the solvability of the subproblems is required. Conditions that ensure these assumptions are discussed in general
and by means of several applications. They include monotone mixed complementarity problems, Karush-Kuhn-Tucker systems arising
from nonlinear programs, and nonlinear equations. Particular results deal with error bounds and upper Lipschitz-continuity
properties for these problems.
Received: November 2001 / Accepted: November 2002 Published online: December 9, 2002
Key Words. generalized equation – nonisolated solutions – Newton's method – superlinear convergence – upper Lipschitz-continuity – mixed
complementarity problem – error bounds
Mathematics Subject Classification (1991): 90C30, 65K05, 90C31, 90C33 相似文献
999.
1000.