全文获取类型
收费全文 | 11138篇 |
免费 | 1035篇 |
国内免费 | 679篇 |
专业分类
化学 | 1341篇 |
晶体学 | 147篇 |
力学 | 1018篇 |
综合类 | 113篇 |
数学 | 8077篇 |
物理学 | 2156篇 |
出版年
2024年 | 23篇 |
2023年 | 95篇 |
2022年 | 137篇 |
2021年 | 137篇 |
2020年 | 284篇 |
2019年 | 291篇 |
2018年 | 286篇 |
2017年 | 333篇 |
2016年 | 327篇 |
2015年 | 272篇 |
2014年 | 472篇 |
2013年 | 991篇 |
2012年 | 419篇 |
2011年 | 605篇 |
2010年 | 596篇 |
2009年 | 697篇 |
2008年 | 767篇 |
2007年 | 713篇 |
2006年 | 634篇 |
2005年 | 594篇 |
2004年 | 487篇 |
2003年 | 464篇 |
2002年 | 413篇 |
2001年 | 343篇 |
2000年 | 294篇 |
1999年 | 286篇 |
1998年 | 222篇 |
1997年 | 203篇 |
1996年 | 190篇 |
1995年 | 146篇 |
1994年 | 123篇 |
1993年 | 108篇 |
1992年 | 95篇 |
1991年 | 73篇 |
1990年 | 69篇 |
1989年 | 46篇 |
1988年 | 51篇 |
1987年 | 33篇 |
1986年 | 56篇 |
1985年 | 54篇 |
1984年 | 59篇 |
1983年 | 41篇 |
1982年 | 59篇 |
1981年 | 50篇 |
1980年 | 46篇 |
1979年 | 49篇 |
1978年 | 31篇 |
1977年 | 19篇 |
1976年 | 23篇 |
1973年 | 13篇 |
排序方式: 共有10000条查询结果,搜索用时 9 毫秒
91.
In this paper the sufficient conditions for the existence of positive solutions of the neutral difference equations with positive and negative coefficients are established. The results improve some known conclusions in the literature 相似文献
92.
A. A. Stahlhofen 《Annalen der Physik》1992,504(7):554-569
The concept of positons, i.e. certain multiparametric solutions of the Korteweg de Vries equation with new properties, is extended to the modified Korteweg de Vries equation. It is shown that the essential features of positons carry over to this case; the collision of positons, the solitary-wave-positon interaction and simple generalizations are discussed in detail. Suggestions for future research and possible applications of the present work are sketched. 相似文献
93.
Rafael Ortega 《Journal of Dynamics and Differential Equations》1992,4(4):651-665
This paper gives sufficient conditions for the existence of periodic solutions of twist type of a time-dependent differential equation of the second order. The concept of periodic solution of twist type is defined in terms of the corresponding Birkhoff normal form and, in particular, implies that the solution is Lyapunov stable. Some applications to nonlocal problems are given. 相似文献
94.
一个反应扩散方程的门槛结果 总被引:4,自引:0,他引:4
本文讨论反应扩散方程Cauchy问题解的整体存在性,渐近性质和Blowup问题.其中或者1<q<p<+∞,n=2.得到门槛结果. 相似文献
95.
96.
Simone Calogero 《Journal of Differential Equations》2004,204(2):323-338
The Nordström-Vlasov system is a Lorentz invariant model for a self-gravitating collisionless gas. We establish suitable a priori bounds on the solutions of this system, which together with energy estimates and the smoothing effect of “momentum averaging” yield the existence of global weak solutions to the corresponding initial value problem. In the process we improve the continuation criterion for classical solutions which was derived recently. The weak solutions are shown to preserve mass. 相似文献
97.
This paper studies the problem of uniformly dissipative solutions of somefifth order non-linear differential equations by the use of frequency domaintechnique. We use the generalized theorem of Yacubovich on dissipativity toobtain some new sufficient conditions of the existence of solutions that aredissipative for (1.1) and (1.2). 相似文献
98.
99.
We investigate the six-dimensional Schrödinger equation for a three-body system with central pair interactions of a more general form than Coulomb interactions. Regular general and special physical solutions of this equation are represented by infinite asymptotic series in integer powers of the distance between two particles and in the sought functions of the other three-body coordinates. Constructing such functions in angular bases composed of spherical and bispherical harmonics or symmetrized Wigner D-functions is reduced to solving simple recursive algebraic equations. For projections of physical solutions on the angular bases functions, we derive boundary conditions at the pair impact point. 相似文献
100.
Subgame consistency is a fundamental element in the solution of cooperative stochastic differential games. In particular, it ensures that: (i) the extension of the solution policy to a later starting time and to any possible state brought about by the prior optimal behavior of the players would remain optimal; (ii) all players do not have incentive to deviate from the initial plan. In this paper, we develop a mechanism for the derivation of the payoff distribution procedures of subgame consistent solutions in stochastic differential games with transferable payoffs. The payoff distribution procedure of the subgame consistent solution can be identified analytically under different optimality principles. Demonstration of the use of the technique for specific optimality principles is shown with an explicitly solvable game. For the first time, analytically tractable solutions of cooperative stochastic differential games with subgame consistency are derived. 相似文献