全文获取类型
收费全文 | 2371篇 |
免费 | 98篇 |
国内免费 | 157篇 |
专业分类
化学 | 6篇 |
力学 | 54篇 |
综合类 | 30篇 |
数学 | 2288篇 |
物理学 | 248篇 |
出版年
2024年 | 3篇 |
2023年 | 25篇 |
2022年 | 16篇 |
2021年 | 39篇 |
2020年 | 25篇 |
2019年 | 53篇 |
2018年 | 49篇 |
2017年 | 52篇 |
2016年 | 41篇 |
2015年 | 45篇 |
2014年 | 79篇 |
2013年 | 193篇 |
2012年 | 74篇 |
2011年 | 93篇 |
2010年 | 81篇 |
2009年 | 134篇 |
2008年 | 173篇 |
2007年 | 167篇 |
2006年 | 135篇 |
2005年 | 116篇 |
2004年 | 98篇 |
2003年 | 109篇 |
2002年 | 122篇 |
2001年 | 73篇 |
2000年 | 96篇 |
1999年 | 61篇 |
1998年 | 50篇 |
1997年 | 76篇 |
1996年 | 42篇 |
1995年 | 43篇 |
1994年 | 30篇 |
1993年 | 23篇 |
1992年 | 23篇 |
1991年 | 12篇 |
1990年 | 23篇 |
1989年 | 12篇 |
1988年 | 13篇 |
1987年 | 18篇 |
1986年 | 8篇 |
1985年 | 15篇 |
1984年 | 12篇 |
1983年 | 5篇 |
1982年 | 14篇 |
1981年 | 15篇 |
1980年 | 7篇 |
1979年 | 9篇 |
1978年 | 6篇 |
1977年 | 11篇 |
1976年 | 2篇 |
1975年 | 2篇 |
排序方式: 共有2626条查询结果,搜索用时 15 毫秒
141.
The purpose of this work is to describe an abstract theory of Hardy-Sobolev spaces on doubling Riemannian manifolds via an atomic decomposition. We study the real interpolation of these spaces with Sobolev spaces and finally give applications to Riesz inequalities. 相似文献
142.
We study the relationship between two classical approaches for quantitative ergodic properties: the first one based on Lyapunov type controls and popularized by Meyn and Tweedie, the second one based on functional inequalities (of Poincaré type). We show that they can be linked through new inequalities (Lyapunov-Poincaré inequalities). Explicit examples for diffusion processes are studied, improving some results in the literature. The example of the kinetic Fokker-Planck equation recently studied by Hérau and Nier, Helffer and Nier, and Villani is in particular discussed in the final section. 相似文献
143.
Disjunctive Programs can often be transcribed as reverse convex constrained problems with nondifferentiable constraints and
unbounded feasible regions. We consider this general class of nonconvex programs, called Reverse Convex Programs (RCP), and
show that under quite general conditions, the closure of the convex hull of the feasible region is polyhedral. This development
is then pursued from a more constructive standpoint, in that, for certain special reverse convex sets, we specify a finite
linear disjunction whose closed convex hull coincides with that of the special reverse convex set. When interpreted in the
context of convexity/intersection cuts, this provides the capability of generating any (negative edge extension) facet cut.
Although this characterization is more clarifying than computationally oriented, our development shows that if certain bounds
are available, then convexity/intersection cuts can be strengthened relatively inexpensively. 相似文献
144.
WANG Xinghua~ 《中国科学A辑(英文版)》2005,48(1)
The best quadrature formula has been found in the following sense:for afunction whose norm of the second derivative is bounded by a given constant and thebest quadrature formula for the approximate evaluation of integration of that function canminimize the worst possible error if the values of the function and its derivative at certainnodes are known.The best interpolation formula used to get the quadrature formula aboveis also found.Moreover,we compare the best quadrature formula with the open compoundcorrected trapezoidal formula by theoretical analysis and stochastic experiments. 相似文献
145.
A. Isar A. Sandulescu W. Scheid 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2000,12(1):3-10
By using the Lindblad theory for open quantum systems, an analytical expression of the tunneling probability through an inverted
parabola is obtained. This penetration probability depends on the environment coefficients. It is shown that the tunneling
probability increases with the dissipation and the temperature of the thermal bath.
Received 15 October 1999 and Received in final form 5 January 2000 相似文献
146.
147.
Spatial competition facility location models: Definition,formulation and solution approach 总被引:2,自引:0,他引:2
Models are presented for locating a firm's production facilities and determining production levels at these facilities so as to maximize the firm's profit. These models take into account the changes in price at each of the spatially separated markets that would result from the increase in supply provided by the new facilities and also from the response of competing firms. Two different models of spatial competition are presented to represent the competitive market situation in which the firm's production facilities are being located. These models are formulated as variational inequalities; recent sensitivity analysis results for variational inequalities are used to develop derivatives of the prices at each of the spatially separated markets with respect to the production levels at each of the new facilities. These derivatives are used to develop a linear approximation of the implicit function relating prices to productions. A heuristic solution procedure making use of this approximation is proposed. 相似文献
148.
H. Hu 《Journal of Optimization Theory and Applications》2005,126(2):287-308
In this paper, we study geometric condition measures and smoothness condition measures of closed convex sets, bounded linear regularity, and linear regularity. We show that, under certain conditions, the constant for the linear regularity of infinitely many closed convex sets can be characterized by the geometric condition measure of the intersection or by the smoothness condition measure of the intersection. We study also the bounded linear regularity and present some interesting properties of the general linear regularity problem.The author is grateful to the referees for valuable and constructive suggestions. In particular, she thanks a referee for drawing her attention to Corollary 5.14 of Ref. 3, which inspired her to derive Theorem 4.2 and Corollary 4.2 in the revision of this paper. 相似文献
149.
150.
Steen Markvorsen 《Geometriae Dedicata》2008,133(1):7-34
For a given combinatorial graph G a geometrization (G, g) of the graph is obtained by considering each edge of the graph as a 1-dimensional manifold with an associated metric g. In this paper we are concerned with minimal isometric immersions of geometrized graphs (G, g) into Riemannian manifolds (N
n
, h). Such immersions we call minimal webs. They admit a natural ‘geometric’ extension of the intrinsic combinatorial discrete Laplacian. The geometric Laplacian on
minimal webs enjoys standard properties such as the maximum principle and the divergence theorems, which are of instrumental
importance for the applications. We apply these properties to show that minimal webs in ambient Riemannian spaces share several
analytic and geometric properties with their smooth (minimal submanifold) counterparts in such spaces. In particular we use
appropriate versions of the divergence theorems together with the comparison techniques for distance functions in Riemannian
geometry and obtain bounds for the first Dirichlet eigenvalues, the exit times and the capacities as well as isoperimetric
type inequalities for so-called extrinsic R-webs of minimal webs in ambient Riemannian manifolds with bounded curvature.
相似文献