全文获取类型
收费全文 | 1811篇 |
免费 | 127篇 |
国内免费 | 167篇 |
专业分类
化学 | 17篇 |
力学 | 198篇 |
综合类 | 42篇 |
数学 | 1627篇 |
物理学 | 221篇 |
出版年
2024年 | 1篇 |
2023年 | 15篇 |
2022年 | 14篇 |
2021年 | 33篇 |
2020年 | 47篇 |
2019年 | 38篇 |
2018年 | 36篇 |
2017年 | 48篇 |
2016年 | 53篇 |
2015年 | 48篇 |
2014年 | 86篇 |
2013年 | 106篇 |
2012年 | 40篇 |
2011年 | 64篇 |
2010年 | 72篇 |
2009年 | 98篇 |
2008年 | 131篇 |
2007年 | 139篇 |
2006年 | 120篇 |
2005年 | 116篇 |
2004年 | 91篇 |
2003年 | 102篇 |
2002年 | 89篇 |
2001年 | 72篇 |
2000年 | 76篇 |
1999年 | 61篇 |
1998年 | 72篇 |
1997年 | 50篇 |
1996年 | 27篇 |
1995年 | 26篇 |
1994年 | 20篇 |
1993年 | 14篇 |
1992年 | 14篇 |
1991年 | 16篇 |
1990年 | 12篇 |
1989年 | 12篇 |
1988年 | 4篇 |
1987年 | 7篇 |
1986年 | 2篇 |
1985年 | 9篇 |
1984年 | 3篇 |
1983年 | 1篇 |
1982年 | 4篇 |
1981年 | 5篇 |
1980年 | 7篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1974年 | 1篇 |
1971年 | 1篇 |
排序方式: 共有2105条查询结果,搜索用时 15 毫秒
51.
In this article, we prove the existence and multiplicity of non-trivial solutions for an indefinite fractional elliptic equation with magnetic field and concave–convex nonlinearities. Our multiplicity results are based on studying the decomposition of the Nehari manifold. 相似文献
52.
This paper is concerned with the Langford ODE and PDE systems. For the Langford ODE system, the existence of steady-state solutions is firstly obtained by Lyapunov–Schmidt method, and the stability and bifurcation direction of periodic solutions are established. Then for the Langford PDE system, the steady-state bifurcations from simple and double eigenvalues are intensively studied. The techniques of space decomposition and implicit function theorem are adopted to deal with the case of double eigenvalue. Finally, by the center manifold theory and the normal form method, the direction of Hopf bifurcation and the stability of spatially homogeneous and inhomogeneous periodic solutions for the PDE system are investigated. 相似文献
53.
ZHANG YongBing 《中国科学A辑(英文版)》2009,(8)
We use the contact Yamabe flow to find solutions of the contact Yamabe problem on K-contact manifolds. 相似文献
54.
Bi-f-harmonic maps are the critical points of bi-f-energy functional. This class of maps tends to integrate bi-harmonic maps and f-harmonic maps. In this paper, we show that bi-f-harmonic maps are not only an extension of f-harmonic maps but also an extension of bi-harmonic maps, and that there should exist many examples of proper bi-f-harmonic maps.In order to find some concrete examples of proper bi-f-harmonic maps, we study the basic properties of bi-f-harmonic maps from two directions which are conformal maps between the same dimensional manifolds and some special maps from or into a warped product manifold. 相似文献
55.
In this paper, we study gradient solitons to the Ricci flow coupled with harmonic map heat flow. We derive new identities on solitons similar to those on gradient solitons of the Ricci flow. When the soliton is compact, we get a classification result. We also discuss the relation with quasi-Einstein manifolds. 相似文献
56.
We study complex Lagrangian submanifolds of a compact hyper-Kähler manifold and prove two results: (a) that an involution of a hyper-Kähler manifold which is antiholomorphic with respect to one complex structure and which acts non-trivially on the corresponding symplectic form always has a fixed point locus which is complex Lagrangian with respect to one of the other complex structures, and (b) there exist Lagrangian submanifolds which are complex with respect to one complex structure and are not the fixed point locus of any involution which is anti-holomorphic with respect to one of the other complex structures. 相似文献
58.
In this note we consider the Schrödinger equation on compact manifolds equipped with possibly degenerate metrics. We prove Strichartz estimates with a loss of derivatives. The rate of loss of derivatives depends on the degeneracy of metrics. For the non-degenerate case we obtain, as an application of the main result, the same Strichartz estimates as that in the elliptic case. This extends Strichartz estimates for Riemannian metrics proved by Burq-Gérard-Tzvetkov to the non-elliptic case and improves the result by Salort for the degenerate case. We also investigate the optimality of the result for the case on 𝕊3 × 𝕊3. 相似文献
59.
In this note, we prove that the CR manifold induced from the canonical parabolic geometry of a quaternionic contact (qc) manifold via a Fefferman-type construction is equivalent to the CR twistor space of the qc manifold defined by O. Biquard. 相似文献
60.
We determine curvature properties of pseudosymmetric type of certain warped product manifolds, and in particular of generalized Robertson–Walker spacetimes, with Einsteinian or quasi-Einsteinian fibre. 相似文献