全文获取类型
收费全文 | 6188篇 |
免费 | 1008篇 |
国内免费 | 493篇 |
专业分类
化学 | 633篇 |
晶体学 | 23篇 |
力学 | 1467篇 |
综合类 | 89篇 |
数学 | 2972篇 |
物理学 | 2505篇 |
出版年
2024年 | 15篇 |
2023年 | 47篇 |
2022年 | 73篇 |
2021年 | 94篇 |
2020年 | 152篇 |
2019年 | 154篇 |
2018年 | 152篇 |
2017年 | 207篇 |
2016年 | 202篇 |
2015年 | 185篇 |
2014年 | 290篇 |
2013年 | 495篇 |
2012年 | 362篇 |
2011年 | 387篇 |
2010年 | 341篇 |
2009年 | 391篇 |
2008年 | 437篇 |
2007年 | 398篇 |
2006年 | 361篇 |
2005年 | 391篇 |
2004年 | 291篇 |
2003年 | 327篇 |
2002年 | 244篇 |
2001年 | 235篇 |
2000年 | 191篇 |
1999年 | 198篇 |
1998年 | 159篇 |
1997年 | 131篇 |
1996年 | 116篇 |
1995年 | 97篇 |
1994年 | 92篇 |
1993年 | 69篇 |
1992年 | 39篇 |
1991年 | 40篇 |
1990年 | 32篇 |
1989年 | 36篇 |
1988年 | 38篇 |
1987年 | 33篇 |
1986年 | 19篇 |
1985年 | 28篇 |
1984年 | 21篇 |
1983年 | 12篇 |
1982年 | 24篇 |
1981年 | 20篇 |
1980年 | 13篇 |
1979年 | 14篇 |
1978年 | 9篇 |
1977年 | 5篇 |
1976年 | 8篇 |
1974年 | 4篇 |
排序方式: 共有7689条查询结果,搜索用时 15 毫秒
31.
32.
This article studies the inshore-offshore fishery model with impulsive diffusion. The existence and global asymptotic stability of both the trivial periodic solution and the positive periodic solution are obtained. The complexity of this system is also analyzed. Moreover, the optimal harvesting policy are given for the inshore subpopulation, which includes the maximum sustainable yield and the corresponding harvesting effort. 相似文献
33.
Piotr Szopa 《Mathematical Methods in the Applied Sciences》2007,30(3):331-346
In this paper, we prove the existence and uniqueness of a global solution for 2‐D micropolar fluid equation with periodic boundary conditions. Then we restrict ourselves to the autonomous case and show the existence of a global attractor. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
34.
Banach空间二阶周期边值问题解的存在性 总被引:2,自引:0,他引:2
利用一些比较结果,讨论了Banach空间中二阶周期边值问题解的存在性,获得了若干解的存在性与唯一性结果。 相似文献
35.
The theory of monotone semiflows has been widely applied to functional differential equations (FDEs). The studies on the theory and applications of monotone semiflows for FDEs are very important and interesting. A brief des-cription of our recent works are as follows.By using general monotone semiflow theory, several results of positively invariant sets, monotone solutions and contracting rectangles of retarded functional differential equations(RFDEs) with infinite delay are gained under the assumption of quasimonotonicity; sufficient conditions for the existence, un-iqueness and global attractivity of periodic solutions are also established by combining the theory of monotone semiflows for neutral functional differential equations(NFDEs) and Krasnoselskii's fixed point theorem. 相似文献
36.
37.
Nguyen Minh Chuong Bui Kien Cuong 《Proceedings of the American Mathematical Society》2004,132(12):3589-3597
A class of Cauchy problems for interesting complicated periodic pseudodifferential equations is considered. By the Galerkin-wavelet method and with weak solutions one can find sufficient conditions to establish convergence estimates of weak Galerkin-wavelet solutions to a Cauchy problem for this class of equations.
38.
YAN Zhen-Ya 《理论物理通讯》2003,39(2)
More recently, sixteen families of Jacobian elliptic function solutions of mKdV equation have been foundby using our extended Jacobian elliptic function expansion method. In this paper, we continue to improve our methodby using another eight pairs of the closed Jacobian elliptic functions. The mKdV equation is chosen to illustrate theimproved method such that another eight families of new Jacobian elliptic function solutions are obtained again. Thenew method can be more powerful to be applied to other nonlinear differential equations. 相似文献
39.
The periodic precipitation pattern formation in gelatinous media is interpreted as a moving boundary problem. The time law,
spacing law and width law are revisited on the basis of the new scenario. The explicit dependence of the geometric structure
on the initial concentrations of the reactants is derived. Matalon—Packter law, which relates the spacing coefficient with
the initial concentrations is reformulated removing many ambiguities and impractical parameters. Experimental results are
discussed to establish the significance of moving boundary concept in the diffusion controlled pattern forming systems 相似文献
40.