全文获取类型
收费全文 | 1136篇 |
免费 | 63篇 |
国内免费 | 118篇 |
专业分类
化学 | 194篇 |
力学 | 21篇 |
综合类 | 15篇 |
数学 | 927篇 |
物理学 | 160篇 |
出版年
2024年 | 2篇 |
2023年 | 16篇 |
2022年 | 19篇 |
2021年 | 13篇 |
2020年 | 29篇 |
2019年 | 29篇 |
2018年 | 38篇 |
2017年 | 31篇 |
2016年 | 30篇 |
2015年 | 21篇 |
2014年 | 37篇 |
2013年 | 122篇 |
2012年 | 26篇 |
2011年 | 69篇 |
2010年 | 64篇 |
2009年 | 109篇 |
2008年 | 104篇 |
2007年 | 77篇 |
2006年 | 64篇 |
2005年 | 43篇 |
2004年 | 46篇 |
2003年 | 42篇 |
2002年 | 45篇 |
2001年 | 33篇 |
2000年 | 29篇 |
1999年 | 29篇 |
1998年 | 26篇 |
1997年 | 30篇 |
1996年 | 16篇 |
1995年 | 13篇 |
1994年 | 5篇 |
1993年 | 9篇 |
1992年 | 7篇 |
1991年 | 2篇 |
1990年 | 4篇 |
1989年 | 2篇 |
1988年 | 3篇 |
1987年 | 3篇 |
1986年 | 3篇 |
1985年 | 4篇 |
1983年 | 2篇 |
1982年 | 4篇 |
1981年 | 4篇 |
1977年 | 1篇 |
1976年 | 2篇 |
1975年 | 1篇 |
1973年 | 2篇 |
1969年 | 2篇 |
1957年 | 1篇 |
1936年 | 1篇 |
排序方式: 共有1317条查询结果,搜索用时 31 毫秒
1.
This paper infers from a generalized Picone identity the uniqueness of the stable positive solution for a class of semilinear equations of superlinear indefinite type, as well as the uniqueness and global attractivity of the coexistence state in two generalized diffusive prototypes of the symbiotic and competing species models of Lotka–Volterra. The optimality of these uniqueness theorems reveals the tremendous strength of the Picone identity. 相似文献
2.
Jing Yu Jingwei Han Chuanzhong Li 《Mathematical Methods in the Applied Sciences》2020,43(6):3076-3085
For the orthosymplectic Lie superalgebra , we choose a set of basis matrices. A linear combination of those basis matrices presents a spatial spectral matrix. The compatible condition of the spatial part and the corresponding temporal parts of the spectral problem leads to a generalized super AKNS (GSAKNS) hierarchy. By making use of the supertrace identity, the obtained GSAKNS hierarchy can be written as the super bi-Hamiltonian structures. 相似文献
3.
4.
Zuo LIU Zhen De WU 《数学学报(英文版)》2005,21(5):997-1000
Let κ be non-negative integer. The unoriented bordism classes, which can be represented as [RP(ξ^κ)] where ξ^κ is a k-plane bundle, form an ideal of the unoriented bordism ring MO.. A group of generators of this ideal expressed by a base of MO. and a necessary and sufficient condition for a bordism class to belong to this ideal are given. 相似文献
5.
Continuous dependence on a modelling parameter is established for solutions of a problem for a complex Ginzburg–Landau equation. A homogenizing boundary condition is also used to discuss the continuous dependence results. We derive a priori estimates that indicate that solutions depend continuously on a parameter in the governing differential equation. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
6.
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
7.
Jacob Fox 《Journal of Combinatorial Theory, Series A》2006,113(1):84-100
We prove that Rado's Boundedness Conjecture from Richard Rado's 1933 famous dissertation Studien zur Kombinatorik is true if it is true for homogeneous equations. We then prove the first nontrivial case of Rado's Boundedness Conjecture: if a1,a2, and a3 are integers, and if for every 24-coloring of the positive integers (or even the nonzero rational numbers) there is a monochromatic solution to the equation a1x1+a2x2+a3x3=0, then for every finite coloring of the positive integers there is a monochromatic solution to a1x1+a2x2+a3x3=0. 相似文献
8.
This work develops the dynamics of a perfectly elastic solid model for application to the outer crust of a magnetised neutron
star. Particular attention is given to the Noether identities responsible for energy-momentum conservation, using a formulation
that is fully covariant, not only (as is usual) in a fully relativistic treatment but also (sacrificing accuracy and elegance
for economy of degrees of gravitational freedom) in the technically more complicated case of the Newtonian limit. The results
are used to obtain explicit (relativistic and Newtonian) formulae for the propagation speeds of generalised (Alfven type)
magneto-elastic perturbation modes. 相似文献
9.
本文研究了一个二阶微分方程的解及其振动性质,利用它获得了一般二阶自共轭方程的振动性判别准则,特别对其中一类二阶微分方程的振动性给出了定量的判别方法.推广了E.Hille的工作,使E.Hille的研究结论成为本文结果的极特殊的情形,同时对一类具有“积分小”系数或可化为具有“积分小”系数的二阶微分方程的振动性与非振动性给出了简便、精确的判别方法. 相似文献
10.
V. Yu. Popov 《Siberian Mathematical Journal》2002,43(5):910-919
No algorithm determines from an arbitrary recursive system of semigroup identities whether the variety defined by this system is finitely based. 相似文献