全文获取类型
收费全文 | 12266篇 |
免费 | 914篇 |
国内免费 | 1086篇 |
专业分类
化学 | 1145篇 |
晶体学 | 8篇 |
力学 | 684篇 |
综合类 | 169篇 |
数学 | 9325篇 |
物理学 | 2935篇 |
出版年
2024年 | 18篇 |
2023年 | 118篇 |
2022年 | 172篇 |
2021年 | 154篇 |
2020年 | 273篇 |
2019年 | 323篇 |
2018年 | 283篇 |
2017年 | 341篇 |
2016年 | 336篇 |
2015年 | 314篇 |
2014年 | 566篇 |
2013年 | 959篇 |
2012年 | 517篇 |
2011年 | 692篇 |
2010年 | 594篇 |
2009年 | 771篇 |
2008年 | 883篇 |
2007年 | 890篇 |
2006年 | 782篇 |
2005年 | 686篇 |
2004年 | 542篇 |
2003年 | 566篇 |
2002年 | 467篇 |
2001年 | 394篇 |
2000年 | 353篇 |
1999年 | 316篇 |
1998年 | 313篇 |
1997年 | 301篇 |
1996年 | 218篇 |
1995年 | 140篇 |
1994年 | 127篇 |
1993年 | 97篇 |
1992年 | 80篇 |
1991年 | 82篇 |
1990年 | 54篇 |
1989年 | 54篇 |
1988年 | 74篇 |
1987年 | 37篇 |
1986年 | 38篇 |
1985年 | 55篇 |
1984年 | 41篇 |
1983年 | 26篇 |
1982年 | 32篇 |
1981年 | 44篇 |
1980年 | 24篇 |
1979年 | 28篇 |
1978年 | 25篇 |
1977年 | 20篇 |
1976年 | 19篇 |
1973年 | 7篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
For an arbitrary bounded closed set E in the complex plane with complement Ω of finite connectivity, we study the degree of convergence of the lemniscates in Ω. 相似文献
32.
林正炎 《数学物理学报(B辑英文版)》2003,23(3)
Let {X_n, n≥1} be a strictly stationary sequence of random variables, whichare either associated or negatively associated, f(·) be their common density. In this paper,the author shows a central limit theorem for a kernel estimate of f(·) under certain regularconditions. 相似文献
33.
34.
We study initial boundary value problems for linear scalar evolutionpartial differential equations, with spatial derivatives ofarbitrary order, posed on the domain {t > 0, 0 < x <L}. We show that the solution can be expressed as an integralin the complex k-plane. This integral is defined in terms ofan x-transform of the initial condition and a t-transform ofthe boundary conditions. The derivation of this integral representationrelies on the analysis of the global relation, which is an algebraicrelation defined in the complex k-plane coupling all boundaryvalues of the solution. For particular cases, such as the case of periodic boundaryconditions, or the case of boundary value problems for even-orderPDEs, it is possible to obtain directly from the global relationan alternative representation for the solution, in the formof an infinite series. We stress, however, that there existinitial boundary value problems for which the only representationis an integral which cannot be written as an infinite series.An example of such a problem is provided by the linearized versionof the KdV equation. Similarly, in general the solution of odd-orderlinear initial boundary value problems on a finite intervalcannot be expressed in terms of an infinite series. 相似文献
35.
Ergodic isospectral theory of the Lax pairs of Euler equations with harmonic analysis flavor 总被引:2,自引:0,他引:2
Y. Charles Li 《Proceedings of the American Mathematical Society》2005,133(9):2681-2687
Isospectral theory of the Lax pairs of both 3D and 2D Euler equations of inviscid fluids is developed. Eigenfunctions are represented through an ergodic integral. The Koopman group and mean ergodic theorem are utilized. Further harmonic analysis results on the ergodic integral are introduced. The ergodic integral is a limit of the oscillatory integral of the first kind.
36.
Anatoliy Samoilenko Manuel Pinto Sergei Trofimchuk 《Proceedings of the American Mathematical Society》2005,133(1):145-154
We apply the Krylov and Bogolyubov asymptotic integration procedure to asymptotically autonomous systems. First, we consider linear systems with quasi-periodic coefficient matrix multiplied by a scalar factor vanishing at infinity. Next, we study the asymptotically autonomous Van-der-Pol oscillator.
37.
38.
Bogdan Ka
mierczak Kazimierz Piechr 《Mathematical Methods in the Applied Sciences》2004,27(11):1317-1345
In this paper we study travelling wave solutions to a system of four non‐linear partial differential equations, which arise in a tissue interaction model for skin morphogenesis. Under the ‘small‐stress’ assumption we prove the existence and uniqueness (up to a translation) of solutions with the dermis and epidermis cell densities being positive, which are a perturbation of a uniform epidermal cell density. We discuss the problem of the minimal wave‐speed. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
39.
多小波子空间上的单小波表示 总被引:1,自引:0,他引:1
本文在较弱的条件下,建立了2重多小波子空间与单小波子空间的关系.即由2重多小波构造出单小波.一方面,这种单小波的平移伸缩与2重多小波的平移伸缩生成的子空间是完全相同的;另一方面,它具有插值性.因此通过构造出的单小波建立了多小波子空间上的Shannon型采样定理. 相似文献
40.
研究了Birkhoff系统的Hojman定理的几何基础.建立了系统的运动微分方程和Hojman守恒 定理,利用现代微分几何给出了Birkhoff系统的Hojman定理的一个证明.
关键词:
Birkhoff系统
Hojman定理
对称性
微分几何 相似文献