全文获取类型
收费全文 | 2347篇 |
免费 | 95篇 |
国内免费 | 155篇 |
专业分类
化学 | 11篇 |
力学 | 49篇 |
综合类 | 30篇 |
数学 | 2257篇 |
物理学 | 250篇 |
出版年
2024年 | 3篇 |
2023年 | 25篇 |
2022年 | 12篇 |
2021年 | 36篇 |
2020年 | 26篇 |
2019年 | 54篇 |
2018年 | 44篇 |
2017年 | 51篇 |
2016年 | 41篇 |
2015年 | 49篇 |
2014年 | 77篇 |
2013年 | 186篇 |
2012年 | 78篇 |
2011年 | 86篇 |
2010年 | 83篇 |
2009年 | 135篇 |
2008年 | 170篇 |
2007年 | 166篇 |
2006年 | 131篇 |
2005年 | 115篇 |
2004年 | 95篇 |
2003年 | 108篇 |
2002年 | 122篇 |
2001年 | 74篇 |
2000年 | 94篇 |
1999年 | 63篇 |
1998年 | 51篇 |
1997年 | 73篇 |
1996年 | 41篇 |
1995年 | 43篇 |
1994年 | 32篇 |
1993年 | 24篇 |
1992年 | 22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2597条查询结果,搜索用时 197 毫秒
101.
102.
103.
104.
Tams Erdlyi 《Journal of Approximation Theory》2004,131(2):149-156
Let Pn denote the set of all algebraic polynomials of degree at most n with real coefficients. Associated with a set of poles a1,a2,…,an R[-1,1] we define the rational function spaces Associated with a set of poles a1,a2,… R[-1,1], we define the rational function spacesIt is an interesting problem to characterize sets a1,a2,… R[-1,1] for which P(a1,a2,…) is not dense in C[-1,1], where C[-1,1] denotes the space of all continuous functions equipped with the uniform norm on [-1,1]. Akhieser showed that the density of P(a1,a2,…) is characterized by the divergence of the series .In this paper, we show that the so-called Clarkson–Erdős–Schwartz phenomenon occurs in the non-dense case. Namely, if P(a1,a2,…) is not dense in C[-1,1], then it is “very much not so”. More precisely, we prove the following result.Theorem Let a1,a2,… R[-1,1]. Suppose P(a1,a2,…) is not dense in C[-1,1], that is,Then every function in the uniform closure of P(a1,a2,…) in C[-1,1] can be extended analytically throughout the set C -1,1,a1,a2,… . 相似文献
105.
This paper considers the problem of the robust H
filtering for a class of nonlinear discrete-time Markovian jump systems with real time-varying norm-bounded parameter uncertainty. For each mode, the nonlinearity is assumed to satisfy the global Lipschitz conditions and appears in both the state and measured output equations. The problem that we address is the design of a nonlinear filter which ensures robust stochastic stability and a prescribed H
performance level of the filtering error system for all admissible uncertainties. A sufficient condition for the solvability of this problem is obtained in terms of a set of linear matrix inequalities; an explicit expression of a desired nonlinear H
filter is also given. Finally, an example is provided to demonstrate the effectiveness of the proposed approach. 相似文献
106.
F. Barthe 《Journal of Theoretical Probability》2004,17(2):293-308
We study the isoperimetric problem for product probability measures with respect to the uniform enlargement. We construct several examples of measures for which the isoperimetric function of coincides with the one of the infinite product
. This completes earlier works by Bobkov and Houdré. 相似文献
107.
Li-mingWu Zheng-liangZhang 《应用数学学报(英文版)》2004,20(3):357-364
Using the method of Girsanov transformation, we establish the Talagrand‘s T2-inequality for diffusion on the path space C([0, N], R^d) with respect to a uniform metric, with the constant independent of N. This improves the known results for the L2-metric. 相似文献
108.
Susanne C. Brenner. 《Mathematics of Computation》2004,73(247):1067-1087
Korn's inequalities for piecewise vector fields are established. They can be applied to classical nonconforming finite element methods, mortar methods and discontinuous Galerkin methods.
109.
Paul-Andi Nagy Constantin Vernicos 《Transactions of the American Mathematical Society》2004,356(6):2501-2513
We study -dimensional Riemannian manifolds with harmonic forms of constant length and first Betti number equal to showing that they are -step nilmanifolds with some special metrics. We also characterize, in terms of properties on the product of harmonic forms, the left-invariant metrics among them. This allows us to clarify the case of equality in the stable isosytolic inequalities in that setting. We also discuss other values of the Betti number.
110.
An Open Question on Cyclic Relaxation 总被引:1,自引:0,他引:1
Achiya Dax 《BIT Numerical Mathematics》2003,43(5):929-943
The problem discussed in this note is highly interesting. It is related to several dual iterative methods, such as the methods proposed by Kaczmarz, Hildreth, Agmon, Cryer, Mangasarian, Herman, Lent, Censor, and others. Cast as row-action methods these algorithms have been proved as useful tools for solving large convex feasibility problems that arise in medical image reconstruction from projections, in inverse problems in radiation therapy, and in linear programming.The question that we want to answer is how these algorithms behave when the feasible region is empty. It is shown that under certain conditions the primal sequence still converges while the dual sequence {y
k
} obeys the rule y
k
=u
k
+k
v, where {u
k
} is a converging sequence and v is a fixed vector that satisfies A
T
v=0,v0,and,b
T
v>0. It is conjectured that these properties hold whenever the feasible region is empty. However, the validity of this claim remains an open question.This revised version was published online in October 2005 with corrections to the Cover Date. 相似文献