全文获取类型
收费全文 | 55404篇 |
免费 | 4444篇 |
国内免费 | 7311篇 |
专业分类
化学 | 38302篇 |
晶体学 | 1496篇 |
力学 | 1209篇 |
综合类 | 311篇 |
数学 | 13067篇 |
物理学 | 12774篇 |
出版年
2024年 | 105篇 |
2023年 | 723篇 |
2022年 | 1191篇 |
2021年 | 1175篇 |
2020年 | 1527篇 |
2019年 | 1627篇 |
2018年 | 1374篇 |
2017年 | 1642篇 |
2016年 | 1760篇 |
2015年 | 1699篇 |
2014年 | 2348篇 |
2013年 | 4198篇 |
2012年 | 2826篇 |
2011年 | 3902篇 |
2010年 | 3174篇 |
2009年 | 3720篇 |
2008年 | 3986篇 |
2007年 | 3784篇 |
2006年 | 3316篇 |
2005年 | 2913篇 |
2004年 | 2628篇 |
2003年 | 2228篇 |
2002年 | 2302篇 |
2001年 | 1582篇 |
2000年 | 1494篇 |
1999年 | 1337篇 |
1998年 | 1088篇 |
1997年 | 940篇 |
1996年 | 918篇 |
1995年 | 894篇 |
1994年 | 793篇 |
1993年 | 648篇 |
1992年 | 531篇 |
1991年 | 399篇 |
1990年 | 286篇 |
1989年 | 297篇 |
1988年 | 228篇 |
1987年 | 194篇 |
1986年 | 174篇 |
1985年 | 195篇 |
1984年 | 160篇 |
1983年 | 95篇 |
1982年 | 140篇 |
1981年 | 142篇 |
1980年 | 98篇 |
1979年 | 80篇 |
1978年 | 63篇 |
1977年 | 71篇 |
1976年 | 46篇 |
1971年 | 23篇 |
排序方式: 共有10000条查询结果,搜索用时 16 毫秒
41.
We introduce extensions of the Mangasarian-Fromovitz and Abadie constraint qualifications to nonsmooth optimization problems with feasibility given by means of lower-level sets. We do not assume directional differentiability, but only upper semicontinuity of the defining functions. By deriving and reviewing primal first-order optimality conditions for nonsmooth problems, we motivate the formulations of the constraint qualifications. Then, we study their interrelation, and we show how they are related to the Slater condition for nonsmooth convex problems, to nonsmooth reverse-convex problems, to the stability of parametric feasible set mappings, and to alternative theorems for the derivation of dual first-order optimality conditions.In the literature on general semi-infinite programming problems, a number of formally different extensions of the Mangasarian-Fromovitz constraint qualification have been introduced recently under different structural assumptions. We show that all these extensions are unified by the constraint qualification presented here. 相似文献
42.
43.
Mean value in invexity analysis 总被引:1,自引:0,他引:1
In this paper, a generalization of the mean value theorem is considered in the case of functions defined on an invex set with respect to η (which is not necessarily connected). 相似文献
44.
45.
J. Schropp 《Numerische Mathematik》1997,78(1):87-101
Summary. We use the qualitative properties of the solution flow of the gradient equation to compute a local minimum of a real-valued function . Under the regularity assumption of all equilibria we show a convergence result for bounded trajectories of a consistent,
strictly stable linear multistep method applied to the gradient equation. Moreover, we compare the asymptotic features of
the numerical and the exact solutions as done by Humphries, Stuart (1994) and Schropp (1995) for one-step methods. In the
case of -stable formulae this leads to an efficient solver for stiff minimization problems.
Received July 10, 1995 / Revised version received June 27, 1996 相似文献
46.
The purpose of this paper is to give the Reid ``Roundabout Theorem' for quadratic functionals with general boundary conditions.
In particular, we describe the so-called coupled point and regularity condition introduced in [16] in terms of Riccati equation
solutions.
Accepted 27 February 1996 相似文献
47.
48.
49.
Summary. We present a simple proof, based on modified logarithmic Sobolev inequalities, of Talagrand’s concentration inequality for
the exponential distribution. We actually observe that every measure satisfying a Poincaré inequality shares the same concentration
phenomenon. We also discuss exponential integrability under Poincaré inequalities and its consequence to sharp diameter upper
bounds on spectral gaps.
Received: 10 June 1996 / In revised form: 9 August 1996 相似文献
50.
S. A. Denisov 《Integral Equations and Operator Theory》2002,42(2):166-173
We consider the Krein systems. For the set of Stummel class coefficients, we establish the criterion in terms of these coefficients for the system to satisfy the Szegö-type estimate on the spectral measure. 相似文献