全文获取类型
收费全文 | 13304篇 |
免费 | 990篇 |
国内免费 | 857篇 |
专业分类
化学 | 1985篇 |
晶体学 | 148篇 |
力学 | 877篇 |
综合类 | 146篇 |
数学 | 9701篇 |
物理学 | 2294篇 |
出版年
2024年 | 29篇 |
2023年 | 150篇 |
2022年 | 173篇 |
2021年 | 179篇 |
2020年 | 299篇 |
2019年 | 327篇 |
2018年 | 334篇 |
2017年 | 370篇 |
2016年 | 407篇 |
2015年 | 311篇 |
2014年 | 640篇 |
2013年 | 1201篇 |
2012年 | 519篇 |
2011年 | 745篇 |
2010年 | 749篇 |
2009年 | 862篇 |
2008年 | 925篇 |
2007年 | 910篇 |
2006年 | 731篇 |
2005年 | 634篇 |
2004年 | 576篇 |
2003年 | 540篇 |
2002年 | 493篇 |
2001年 | 382篇 |
2000年 | 327篇 |
1999年 | 308篇 |
1998年 | 267篇 |
1997年 | 244篇 |
1996年 | 210篇 |
1995年 | 150篇 |
1994年 | 135篇 |
1993年 | 103篇 |
1992年 | 99篇 |
1991年 | 66篇 |
1990年 | 57篇 |
1989年 | 49篇 |
1988年 | 54篇 |
1987年 | 29篇 |
1986年 | 50篇 |
1985年 | 60篇 |
1984年 | 68篇 |
1983年 | 44篇 |
1982年 | 57篇 |
1981年 | 50篇 |
1980年 | 46篇 |
1979年 | 57篇 |
1978年 | 37篇 |
1977年 | 27篇 |
1976年 | 25篇 |
1973年 | 13篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
81.
吕海深 《Annals of Differential Equations》2004,20(2):133-139
Under suitable conditions on f(·,u), it is shown that the two-point boundaryvalue problem((u'))' + λq(t)f(u) = 0in (0, 1),u(0) = u(1) = 0,has two positive solution or at least one positive solution for λ in a compatibleinterval. 相似文献
82.
Operator Matrix Forms of Positive Operators 总被引:2,自引:0,他引:2
If a 3-tuple (A:H1→H1,B:H2→H1,C:H2→H2)of operators on Hibert spaces is given,we proved that the operator ~↑A:=(↑A ↓B^*↑B ↓C) on H=H1 H2 is ≥0 is and only if A≥0,R(B)∪→R(A^1/2) and C≥B^* A^ b,where A^ is the generalized inverse of A.In general,A^ is a closed operator,but since R(B)∪→R(A^1/2,B^* A^ B is bounded yet. 相似文献
83.
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
84.
Based on the Kachanov method and the alternating iteration technique, a new method is proposed to deal with the problem of the strongly interacted multiple cracks in an infinite plate. Unlike the Kachanov method which neglects the interaction of the tractions of the non-uniform components, the tractions of the non-uniform components on the surfaces of cracks are considered through the alternating technique. The accuracy and efficiency of present method are validated by comparing the results of two collinear and two parallel overlapped open the cracks obtained by the present method with those of the exact solutions, the results of the Kachanov method and the alternating iteration technique. Applications of present method in solving sliding close crack problems and evaluating the plastic zones demonstrate the versatility of present method. 相似文献
85.
This paper presents an algorithm and the supporting theory for solving a class of nonlinear multiple criteria optimization problems using Zionts—Wallenius type of interaction. The Zionts—Wallenius method, as extended in this paper, can be used for solving multiple criteria problems with concave objective and (implicit) value functions and convex feasible regions. Modifications of the method to handle nonconvex feasible regions and general nonlinear objective functions are also discussed.This research was supported, in part, by a Faculty Research Development Award and by a Council of 100 Research Grant from Arizona State University (Roy), and by a grant from Y. Jahnsson Foundation, Finland (Wallenius). The research was performed while the second author was a Visiting Professor at Arizona State University. 相似文献
86.
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
87.
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
88.
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
89.
90.
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