全文获取类型
收费全文 | 7184篇 |
免费 | 902篇 |
国内免费 | 639篇 |
专业分类
化学 | 220篇 |
力学 | 886篇 |
综合类 | 188篇 |
数学 | 6024篇 |
物理学 | 1407篇 |
出版年
2024年 | 17篇 |
2023年 | 62篇 |
2022年 | 97篇 |
2021年 | 110篇 |
2020年 | 178篇 |
2019年 | 163篇 |
2018年 | 199篇 |
2017年 | 233篇 |
2016年 | 267篇 |
2015年 | 171篇 |
2014年 | 304篇 |
2013年 | 518篇 |
2012年 | 294篇 |
2011年 | 379篇 |
2010年 | 356篇 |
2009年 | 416篇 |
2008年 | 500篇 |
2007年 | 491篇 |
2006年 | 463篇 |
2005年 | 432篇 |
2004年 | 379篇 |
2003年 | 336篇 |
2002年 | 328篇 |
2001年 | 251篇 |
2000年 | 281篇 |
1999年 | 216篇 |
1998年 | 202篇 |
1997年 | 180篇 |
1996年 | 125篇 |
1995年 | 140篇 |
1994年 | 87篇 |
1993年 | 86篇 |
1992年 | 72篇 |
1991年 | 51篇 |
1990年 | 60篇 |
1989年 | 39篇 |
1988年 | 24篇 |
1987年 | 26篇 |
1986年 | 22篇 |
1985年 | 24篇 |
1984年 | 21篇 |
1983年 | 9篇 |
1982年 | 19篇 |
1981年 | 11篇 |
1980年 | 16篇 |
1979年 | 9篇 |
1978年 | 13篇 |
1977年 | 14篇 |
1974年 | 8篇 |
1973年 | 7篇 |
排序方式: 共有8725条查询结果,搜索用时 0 毫秒
1.
This work is concerned with the extension of the Jacobi spectral Galerkin method to a class of nonlinear fractional pantograph differential equations. First, the fractional differential equation is converted to a nonlinear Volterra integral equation with weakly singular kernel. Second, we analyze the existence and uniqueness of solutions for the obtained integral equation. Then, the Galerkin method is used for solving the equivalent integral equation. The error estimates for the proposed method are also investigated. Finally, illustrative examples are presented to confirm our theoretical analysis. 相似文献
2.
对由一类非线性抛物型变分不等方程所描述的无穷维动力系统,给出了存在全局吸引子及弱近似惯性流形的充分条件. 相似文献
3.
ZHAO Ren ZHANG Li-Chun HU Shuang-Qi 《理论物理通讯》2006,46(10)
We generalize the method that is used to study corrections to Cardy-Verlinde formula due to generalized uncertainty principle and discuss corrections to Cardy-Verlinde formula due to generalized uncertainty principle in (anti)-de Sitter space. Because in de Sitter black hole spacetime the radiation temperature of the black hole horizon is different from the one of the cosmological horizon, this spacetime is a thermodynamical non-equilibrium spacetime. 相似文献
4.
The multilevel generalized assignment problem is a problem of assigning agents to tasks where the agents can perform tasks at more than one efficiency level. A profit is associated with each assignment and the objective of the problem is profit maximization. Two heuristic solution methods are presented for the problem. The heuristics are developed from solution methods for the generalized assignment problem. One method uses a regret minimization approach whilst the other method uses a repair approach on a relaxation of the problem. The heuristics are able to solve moderately large instances of the problem rapidly and effectively. Procedures for deriving an upper bound on the solution of the problem are also described. On larger and harder instances of the problem one heuristic is particularly effective. 相似文献
5.
In this paper we introduce a generalization of stable sets: stable multi-sets. A stable multi-set is an assignment of integers
to the vertices of a graph, such that specified bounds on vertices and edges are not exceeded. In case all vertex and edge
bounds equal one, stable multi-sets are equivalent to stable sets.
For the stable multi-set problem, we derive reduction rules and study the associated polytope. We state necessary and sufficient
conditions for the extreme points of the linear relaxation to be integer. These conditions generalize the conditions for the
stable set polytope. Moreover, the classes of odd cycle and clique inequalities for stable sets are generalized to stable
multi-sets and conditions for them to be facet defining are determined.
The study of stable multi-sets is initiated by optimization problems in the field of telecommunication networks. Stable multi-sets
emerge as an important substructure in the design of optical networks.
Received: February 14, 2001/Revised version: September 7, 2001 相似文献
6.
陈泽乾 《数学物理学报(B辑英文版)》2002,22(3)
A new framework of Gaussian white noise calculus is established, in line with generalized expansion in [3, 4, 7]. A suitable frame of Fock expansion is presented on Gaussian generalized expansion functionals being introduced here, which provides the integral kernel operator decomposition of the second quantization of Koopman operators for chaotic dynamical systems, in terms of annihilation operators dt and its dual, creation operators t*. 相似文献
7.
Equilibrium Problems with Applications to Eigenvalue Problems 总被引:5,自引:0,他引:5
In this paper, we consider equilibrium problems and introduce the concept of (S)+ condition for bifunctions. Existence results for equilibrium problems with the (S)+ condition are derived. As special cases, we obtain several existence results for the generalized nonlinear variational inequality studied by Ding and Tarafdar (Ref. 1) and the generalized variational inequality studied by Cubiotti and Yao (Ref. 2). Finally, applications to a class of eigenvalue problems are given. 相似文献
8.
本文考察了包括平面上的各种广义 Cantor集 ,Sierpinski集和包括某些连续不可微曲线在内的广义 Sierpinski集 .由相似变换 ,导出了它们的级数表达式 ,并利用它和字符串空间的对应关系 ,计算出它们的Hausdorff维数 相似文献
9.
CONG Fuzhong & LI YongSchool of Mathematics Information Science Shandong Institute of Business Technology Yantai China Office of Mathematics Changchun Flight Academy of the Air Force Changchun China Department of Mathematics Jilin University Changchun China 《中国科学A辑(英文版)》2004,47(5):675-686
An effective stability result for generalized Hamiltonian systems is obtained by applying the simultaneous approximation technique due to Lochak. Among these systems, dimensions of action variables and angle variables might be distinct. 相似文献
10.