全文获取类型
收费全文 | 5131篇 |
免费 | 383篇 |
国内免费 | 455篇 |
专业分类
化学 | 422篇 |
晶体学 | 3篇 |
力学 | 112篇 |
综合类 | 63篇 |
数学 | 2486篇 |
物理学 | 652篇 |
综合类 | 2231篇 |
出版年
2024年 | 5篇 |
2023年 | 43篇 |
2022年 | 66篇 |
2021年 | 89篇 |
2020年 | 97篇 |
2019年 | 104篇 |
2018年 | 101篇 |
2017年 | 115篇 |
2016年 | 132篇 |
2015年 | 111篇 |
2014年 | 199篇 |
2013年 | 269篇 |
2012年 | 253篇 |
2011年 | 271篇 |
2010年 | 245篇 |
2009年 | 323篇 |
2008年 | 321篇 |
2007年 | 369篇 |
2006年 | 352篇 |
2005年 | 315篇 |
2004年 | 279篇 |
2003年 | 234篇 |
2002年 | 227篇 |
2001年 | 173篇 |
2000年 | 184篇 |
1999年 | 166篇 |
1998年 | 123篇 |
1997年 | 147篇 |
1996年 | 96篇 |
1995年 | 75篇 |
1994年 | 83篇 |
1993年 | 65篇 |
1992年 | 55篇 |
1991年 | 57篇 |
1990年 | 29篇 |
1989年 | 32篇 |
1988年 | 38篇 |
1987年 | 28篇 |
1986年 | 20篇 |
1985年 | 16篇 |
1984年 | 14篇 |
1983年 | 5篇 |
1982年 | 8篇 |
1981年 | 6篇 |
1980年 | 6篇 |
1979年 | 7篇 |
1977年 | 6篇 |
1976年 | 4篇 |
1957年 | 1篇 |
1955年 | 1篇 |
排序方式: 共有5969条查询结果,搜索用时 93 毫秒
51.
A systematic study of the upper semicontinuity and the lower semicontinuity of the solution map in parametric affine variational
inequalities is given in this paper. Several examples are constructed to analyze the results.
This work was supported by Korea Research Foundation Grant (KRF 2001-015-DP0049), the APEC Postdoctoral Fellowships Program,
and the KOSEF Brain Pool Program. 相似文献
52.
Let Top
0
be the category of topological T
0-spaces, QU
0
the category of quasi-uniform T
0-spaces, T : QU
0
→ Top
0
the usual forgetful functor and K : QU
0
→ QU
0
the bicompletion reflector with unit k : 1 → K. Any T-section F : Top
0
→ QU
0
is called K-true if KF = FTKF, and upper (lower)
K-true if KF is finer (coarser) than FTKF. The literature considers important T-sections F that enjoy all three, or just one, or none of these properties. It is known that T(K,k)F is well-pointed if and only if F is upper K-true. We prove the surprising fact that T(K,k)F is the reflection to Fix(TkF) whenever it is idempotent. We also prove a new characterization of upper K-trueness. We construct examples to set apart some natural cases. In particular we present an upper K-true F for which T(K,k)F is not idempotent, and a K-true F for which the coarsest associated T-preserving coreflector in QU
0
is not stable under K.
We dedicate this paper to the memory of Sérgio de Ornelas Salbany (1941–2005). 相似文献
53.
Lai-Jiu Lin 《Journal of Global Optimization》2007,38(1):21-39
In this paper, we study an existence theorem of systems of generalized quasivariational inclusions problem. By this result,
we establish the existence theorems of solutions of systems of generalized equations, systems of generalized vector quasiequilibrium
problem, collective variational fixed point, systems of generalized quasiloose saddle point, systems of minimax theorem, mathematical
program with systems of variational inclusions constraints, mathematical program with systems of equilibrium constraints and
systems of bilevel problem and semi-infinite problem with systems of equilibrium problem constraints.
This research was supported by the National Science Council of the Republic of China. 相似文献
54.
55.
Effect of the subdivision strategy on convergence and efficiency of some global optimization algorithms 总被引:2,自引:0,他引:2
Hoang Tuy 《Journal of Global Optimization》1991,1(1):23-36
We investigate subdivision strategies that can improve the convergence and efficiency of some branch and bound algorithms of global optimization. In particular, a general class of so called weakly exhaustive simplicial subdivision processes is introduced that subsumes all previously known radial exhaustive processes. This result provides the basis for constructing flexible subdivision strategies that can be adapted to take advantage of various problem conditions. 相似文献
56.
57.
Jinyan Fan 《Computational Optimization and Applications》2006,34(2):215-227
In this paper, we present the new trust region method for nonlinear equations with the trust region converging to zero. The
new method preserves the global convergence of the traditional trust region methods in which the trust region radius will
be larger than a positive constant. We study the convergence rate of the new method under the local error bound condition
which is weaker than the nonsingularity. An example given by Y.X. Yuan shows that the convergence rate can not be quadratic.
Finally, some numerical results are given.
This work is supported by Chinese NSFC grants 10401023 and 10371076, Research Grants for Young Teachers of Shanghai Jiao Tong
University, and E-Institute of Computational Sciences of Shanghai Universities.
An erratum to this article is available at . 相似文献
58.
Alberto Caprara Andrea Lodi Silvano Martello Michele Monaci 《Discrete Optimization》2006,3(4):317-326
We address the problem of packing a given set of rectangles into the minimum size square. We consider three versions of the problem, arising when the rectangles (i) are squares; (ii) have a fixed orientation; (iii) can be rotated by 90. For each case we study lower bounds, and analyze their worst-case performance ratio. In addition, we evaluate through computational experiments their average performance on instances from the literature. 相似文献
59.
We study the degree distribution of the greatest common divisor of two or more random polynomials over a finite field ??q. We provide estimates for several parameters like number of distinct common irreducible factors, number of irreducible factors counting repetitions, and total degree of the gcd of two or more polynomials. We show that the limiting distribution of a random variable counting the total degree of the gcd is geometric and that the distributions of random variables counting the number of common factors (with and without repetitions) are very close to Poisson distributions when q is large. © 2005 Wiley Periodicals, Inc. Random Struct. Alg., 2006 相似文献
60.
给出了大规模界约束优化的一个子空间截断牛顿法。利用截断牛顿法修正非有效约束所对应的变量,用投影梯度法修正有效约束所对应的变量,文中证明了方法的整体收敛性,并对方法进行了数值试验,且与子空间有限内存拟牛顿法进行了数值比较。 相似文献