全文获取类型
收费全文 | 6688篇 |
免费 | 572篇 |
国内免费 | 604篇 |
专业分类
化学 | 629篇 |
晶体学 | 24篇 |
力学 | 380篇 |
综合类 | 152篇 |
数学 | 5973篇 |
物理学 | 706篇 |
出版年
2024年 | 6篇 |
2023年 | 48篇 |
2022年 | 84篇 |
2021年 | 136篇 |
2020年 | 124篇 |
2019年 | 143篇 |
2018年 | 131篇 |
2017年 | 208篇 |
2016年 | 217篇 |
2015年 | 137篇 |
2014年 | 306篇 |
2013年 | 514篇 |
2012年 | 310篇 |
2011年 | 396篇 |
2010年 | 344篇 |
2009年 | 427篇 |
2008年 | 465篇 |
2007年 | 493篇 |
2006年 | 398篇 |
2005年 | 358篇 |
2004年 | 338篇 |
2003年 | 296篇 |
2002年 | 278篇 |
2001年 | 240篇 |
2000年 | 222篇 |
1999年 | 173篇 |
1998年 | 186篇 |
1997年 | 169篇 |
1996年 | 131篇 |
1995年 | 89篇 |
1994年 | 77篇 |
1993年 | 49篇 |
1992年 | 40篇 |
1991年 | 41篇 |
1990年 | 37篇 |
1989年 | 21篇 |
1988年 | 23篇 |
1987年 | 19篇 |
1986年 | 11篇 |
1985年 | 24篇 |
1984年 | 22篇 |
1983年 | 30篇 |
1982年 | 20篇 |
1981年 | 24篇 |
1980年 | 22篇 |
1979年 | 15篇 |
1978年 | 11篇 |
1977年 | 3篇 |
1969年 | 1篇 |
1959年 | 2篇 |
排序方式: 共有7864条查询结果,搜索用时 46 毫秒
941.
A. M. Chebotarev 《Mathematical Notes》1997,61(4):510-518
We prove that the solution of the Hudson-Parthasarathy quantum stochastic differential equation in the Fock space coincides with the solution of a symmetric boundary value problem for the Schrödinger equation in the interaction representation generated by the energy operator of the environment. The boundary conditions describe the jumps in the phase and the amplitude of the Fourier transforms of the Fock vector components as any of its arguments changes the sign. The corresponding Markov evolution equation (the Lindblad equation or the “master equation”) is derived from the boundary value problem for the Schrödinger equation. 相似文献
942.
高阶拟线性椭圆型方程奇摄动问题 总被引:2,自引:0,他引:2
本文利用微分不等式和多重尺度,研究了一个高阶椭圆型偏微分方程摄动边值问题,并得到了一致有效的渐近展开式。 相似文献
943.
J. -P. Penot 《Journal of Optimization Theory and Applications》1996,90(3):535-554
Two ways of defining a well-conditioned minimization problem are introduced and related, with emphasis on the quantitative aspects. These concepts are used to study the behavior of the solution sets of minimization problems for functions with connected sublevel sets, generalizing results of Attouch-Wets in the convex case. Applications to continuity properties of subdifferentials and to projection mappings are pointed out.We are grateful to M. Valadier for pointing out, during a lecture by the author in Montpellier in October 1990 presenting the main results of the present paper, that existence results in Section 2 of the present paper can be dissociated from estimates. 相似文献
944.
945.
Rinya Takahashi Masaaki Sibuya 《Annals of the Institute of Statistical Mathematics》1996,48(1):127-144
A theorem of this paper proves that if the size distribution of random spheres is generalized gamma, its Wicksell transform and other related distributions belong to the domain of attraction of the Gumbel distribution. The theorem also shows the attraction coefficients of the distributions. The fatigue strength of high-strength steel is closely related to the maximum size of nonmetallic inclusions in the region of maximum stress of the steel. Murakami and others developed a method, making use of the Gumbel QQ-plot, for predicting the maximum size from the size distribution of inclusion circles in microscopic view-fields. Based on the Gumbel approximation of the maximum of wicksell transforms, a modified and extended version of Murakami's method is justified, and its performance is evaluated by simulation. 相似文献
946.
947.
In this paper, an elastic structure model is constructed according to the test data with various confidences and properly
selected analytical parameters (mass matrixM or stiffness matrixK). First, the modeling method is described, and second, the uniqueness of the result is strictly proved. Finally, a numerical
example is given to show the reasonableness of this method and the superiority of the result to that in reference [4]. 相似文献
948.
949.
950.
An asymptotic equivalence theorem is proven between the solutions of the initial value problem in all space for the Boltzmann and Enskog equations for initial data which assure global existence for the solutions to the initial value problem for one of the two equations. The proof is given starting from the solution of the Boltzmann equation, then the proof line is simply indicated when one starts from the Enskog equation. The proof holds for Knudsen numbers of the order of unity and equivalence is proven when the scale of the dimensions of the gas particles characterizing the Enskog equation tends to zero.On leave from Department of Mathematics, University of Warsaw, Poland. 相似文献