全文获取类型
收费全文 | 20826篇 |
免费 | 1431篇 |
国内免费 | 1391篇 |
专业分类
化学 | 1927篇 |
晶体学 | 34篇 |
力学 | 1807篇 |
综合类 | 279篇 |
数学 | 17547篇 |
物理学 | 2054篇 |
出版年
2024年 | 37篇 |
2023年 | 193篇 |
2022年 | 277篇 |
2021年 | 338篇 |
2020年 | 428篇 |
2019年 | 467篇 |
2018年 | 493篇 |
2017年 | 559篇 |
2016年 | 573篇 |
2015年 | 424篇 |
2014年 | 904篇 |
2013年 | 1638篇 |
2012年 | 1000篇 |
2011年 | 1173篇 |
2010年 | 1010篇 |
2009年 | 1400篇 |
2008年 | 1454篇 |
2007年 | 1444篇 |
2006年 | 1251篇 |
2005年 | 1000篇 |
2004年 | 905篇 |
2003年 | 891篇 |
2002年 | 800篇 |
2001年 | 651篇 |
2000年 | 635篇 |
1999年 | 549篇 |
1998年 | 514篇 |
1997年 | 460篇 |
1996年 | 367篇 |
1995年 | 285篇 |
1994年 | 227篇 |
1993年 | 181篇 |
1992年 | 162篇 |
1991年 | 153篇 |
1990年 | 120篇 |
1989年 | 63篇 |
1988年 | 62篇 |
1987年 | 65篇 |
1986年 | 58篇 |
1985年 | 76篇 |
1984年 | 79篇 |
1983年 | 54篇 |
1982年 | 46篇 |
1981年 | 45篇 |
1980年 | 37篇 |
1979年 | 28篇 |
1978年 | 27篇 |
1977年 | 17篇 |
1976年 | 9篇 |
1974年 | 4篇 |
排序方式: 共有10000条查询结果,搜索用时 250 毫秒
91.
Riad Hassani Patrick Hild Ioan Ionescu 《Mathematical Methods in the Applied Sciences》2004,27(1):47-67
We consider the Signorini problem with Coulomb friction in elasticity. Sufficient conditions of non‐uniqueness are obtained for the continuous model. These conditions are linked to the existence of real eigenvalues of an operator in a Hilbert space. We prove that, under appropriate conditions, real eigenvalues exist for a non‐local Coulomb friction model. Finite element approximation of the eigenvalue problem is considered and numerical experiments are performed. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
92.
L. E. Payne P. W. Schaefer J. C. Song 《Mathematical Methods in the Applied Sciences》2004,27(17):2045-2053
Energy bounds are derived for Dirichlet type boundary value problems for the Navier–Stokes and Stokes equations when a combination of the solution values initially and at a later time is prescribed. The bounds are obtained by means of a differential inequality and imply uniqueness and continuous data dependence of the solutions for a range of values of the parameter in the non‐standard auxiliary condition. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
93.
We study the complex Ginzburg–Landau equation with zero Neumann boundary conditions on a finite interval and establish that this boundary problem (with suitably chosen parameters) has countably many stable two-dimensional self-similar tori. The case of periodic boundary conditions is also investigated. 相似文献
94.
本文通过研究匹配问题的实例空间,匈牙利算法和解空间三者之间的关系,指出S实例空间的数目与问题复杂度之间的关系既不是充分也不是必要的,而如何对问题的解空间进行合理的分解才能是问题的关键。 相似文献
95.
96.
Kinetic selection principles have been shown to be useful and physically reasonable in nonlinear hyperbolic problems with
large amplitude phase transitions. We refer to Abeyaratne and Knowles, [A-K], for discussion on the subject. They also have
been used for degenerate nonlinear problems, where the genuine nonlinearity property of Lax is violated. This is the framework
of Liu, [Li], in the kinetic situation of Hayes and Le Floch, [H-L], where their so-called non classical shocks may be seen
as small amplitude phase transitions. Here, we describe the local geometry generated by the generic non genuinely nonlinear
assumption. A geometric kinetic criterion can be used to select indeterminate simple waves and obtain the well-posedness of
the local Riemann problem. A particular case is the entropic kinetic criterion of Hayes and Le Floch.
Sunto Principi di selezione cinetica sono stati mostrati utili e fisicamente ragionevoli in problemi iperbolici con transizioni di fase di grande ampiezza. Ci riferiamo ad Abeyaratne e Knowles, [A-K], per discussioni sull'argomento. Detti principi sono stati usati per problemi nonlineari degeneri, dove la proprietà di genuina nonlinearità di Lax è violata. Questo è la prospettiva di Liu, [Li], nella situazione cinetica di Hayes e Le Floch, [H-L], dove i loro così detti urti non classici possono essere considerati come transizioni di fase di piccola ampiezza. Qui, descriviamo la geometria locale generata dall'ipotesi generica genuinamente nonlineare. Un criterio di geometria cinetica può essere usato per selezionare onde semplici indeterminate ed ottenere la buona posizione per il problema locale di Riemann. Un caso particolare è il criterio di entropia cinetico di Hayes e Le Floc.相似文献
97.
The main purpose of this paper is to use a mean value theorem of Dirichlet L-functions to study the asymptotic property of a hybrid mean value of a generalized Cochrane sum, and give an interesting mean value formula.2000 Mathematics Subject Classification: Primary—11F20; Secondary—11F99 相似文献
98.
反对称正交对称矩阵反问题 总被引:6,自引:0,他引:6
本文讨论一类反对称正交对称矩阵反问题及其最佳逼近.研究了这类矩阵的一些性质,利用这些性质给出了反问题解存在的一些条件和解的一般表达式,不仅证明了最佳逼近解的存在唯一性,而且给出了此解的具体表达式. 相似文献
99.
Francesc Carreras M. Dolors Llongueras Antonio Magaña 《Annals of Operations Research》2005,137(1):67-89
A partnership in a cooperative game is a coalition that possesses an internal structure and, simultaneously, behaves as an
individual member. Forming partnerships leads to a modification of the original game which differs from the quotient game
that arises when one or more coalitions are actually formed.
In this paper, the Shapley value is used to discuss the convenience to form either coalitions or partnerships. To this end,
the difference between the additive Shapley value of the partnership in the partnership game and the Shapley alliance value
of the coalition, and also between the corresponding value of the internal and external players, are analysed. Simple games
are especially considered.
Research partially supported by Grant BFM 2003-01314 of the Science and Technology Spanish Ministry and the European Regional
Development Fund. 相似文献
100.
一类具有非局部反应扩散方程的奇摄动问题 总被引:7,自引:0,他引:7
本文讨论一类具非局部反应扩散方程的奇摄动初始边值问题,利用迭代法及微分不等式,研究了初始边值问题的存在唯一及其渐近性态。 相似文献