全文获取类型
收费全文 | 905篇 |
免费 | 65篇 |
国内免费 | 51篇 |
专业分类
化学 | 97篇 |
力学 | 35篇 |
综合类 | 9篇 |
数学 | 565篇 |
物理学 | 72篇 |
综合类 | 243篇 |
出版年
2023年 | 4篇 |
2022年 | 4篇 |
2021年 | 6篇 |
2020年 | 14篇 |
2019年 | 13篇 |
2018年 | 17篇 |
2017年 | 21篇 |
2016年 | 12篇 |
2015年 | 13篇 |
2014年 | 16篇 |
2013年 | 50篇 |
2012年 | 17篇 |
2011年 | 26篇 |
2010年 | 14篇 |
2009年 | 40篇 |
2008年 | 46篇 |
2007年 | 47篇 |
2006年 | 67篇 |
2005年 | 50篇 |
2004年 | 51篇 |
2003年 | 44篇 |
2002年 | 44篇 |
2001年 | 58篇 |
2000年 | 35篇 |
1999年 | 28篇 |
1998年 | 40篇 |
1997年 | 29篇 |
1996年 | 25篇 |
1995年 | 21篇 |
1994年 | 18篇 |
1993年 | 16篇 |
1992年 | 14篇 |
1991年 | 14篇 |
1990年 | 15篇 |
1989年 | 9篇 |
1988年 | 15篇 |
1987年 | 5篇 |
1986年 | 8篇 |
1985年 | 7篇 |
1984年 | 10篇 |
1983年 | 3篇 |
1982年 | 9篇 |
1981年 | 10篇 |
1980年 | 4篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1977年 | 5篇 |
1976年 | 4篇 |
1975年 | 1篇 |
排序方式: 共有1021条查询结果,搜索用时 15 毫秒
1.
徐传胜 《科技导报(北京)》2021,39(7):120-124
李雅普诺夫是圣彼得堡数学学派的中流砥柱,创立了运动稳定性理论、旋转液团平衡形状理论和微分方程定性理论,探索了概率论中心极限定理和一系列其他深刻数学力学问题,为俄罗斯跻身世界科技强国做出了卓越贡献。通过采撷李雅普诺夫的动人爱情诗篇和唯美科学奋斗目标,展示了其美丽的爱情观和追求卓越的科学精神、人生观和宇宙观。 相似文献
2.
Piotr Garbaczewski 《Journal of statistical physics》2006,123(2):315-355
We analyze the functioning of Gibbs-type entropy functionals in the time domain, with emphasis on Shannon and Kullback-Leibler entropies of time-dependent continuous probability distributions. The Shannon entropy validity is extended to probability distributions inferred from L
2(R
n
) quantum wave packets. In contrast to the von Neumann entropy which simply vanishes on pure states, the differential entropy quantifies the degree of probability (de)localization and its time development. The associated dynamics of the Fisher information functional quantifies nontrivial power transfer processes in the mean, both in dissipative and quantum mechanical cases.
PACS NUMBERS: 05.45.+b, 02.50.-r, 03.65.Ta, 03.67.-a 相似文献
3.
4.
In this paper we define trace functionals on the algebra of pseudo-differential operators with cone-shaped exits to infinity. Furthermore, we improve the Weyl formula on the asymptotic distribution of eigenvalues and make use of it in order to establish inclusion relations between the interpolation normed ideals of compact operators in L
2(R
n
) and the above operator classes. 相似文献
5.
Miklós Csörgő 《Periodica Mathematica Hungarica》2005,50(1-2):1-27
Summary This article provides a glimpse of some of the highlights of the joint work of Endre Csáki and Pál Révész since 1979. The topics of this short exploration of the rich stochastic milieu of this inspiring collaboration revolve around Brownian motion, random walks and their long excursions, local times and additive functionals, iterated processes, almost sure local and global central limit theorems, integral functionals of geometric stochastic processes, favourite sites--favourite values and jump sizes for random walk and Brownian motion, random walking in a random scenery, and large void zones and occupation times for coalescing random walks. 相似文献
6.
关于Banach空间中凸泛函的广义次梯度不等式 总被引:2,自引:0,他引:2
本文在前人^[1,2]的基础之上,以凸泛函的次梯度不等式为工具,将Jensen不等式推广到Banach空间中的凸泛函,导出了Banach空间中的Bochner积分型的广义Jensen不等式,给出其在Banach空间概率论中某些应用,从而推广了文献[3—6]的工作. 相似文献
7.
In this paper, we investigate a constrained optimization problem with a quadratic cost functional and two quadratic equality constraints. It is assumed that the cost functional is positive definite and that the constraints are both feasible and regular (but otherwise they are unrestricted quadratic functions). Thus, the existence of a global constrained minimum is assured. We develop a necessary and sufficient condition that completely characterizes the global minimum cost. Such a condition is of essential importance in iterative numerical methods for solving the constrained minimization problem, because it readily distinguishes between local minima and global minima and thus provides a stopping criterion for the computation. The result is similar to one obtained previously by the authors. In the previous result, we gave a characterization of the global minimum of a constrained quadratic minimization problem in which the cost functional was an arbitrary quadratic functional (as opposed to positive-definite here) and the constraints were at least positive-semidefinite quadratic functions (as opposed to essentially unrestricted here). 相似文献
8.
By an elementary calculation we obtain the exact mean values of Minkowksi functionals for a standard model of percolating sets. In particular, a recurrence theorem for the mean Euler characteristic recently put forward is shown to be incorrect. Related previous mathematical work is mentioned. We also conjecture bounds for the threshold density of continuum percolation, which are associated with the Euler characteristic. 相似文献
9.
Ryusuke Kon 《Proceedings of the American Mathematical Society》2006,134(10):3025-3034
We establish an exclusion principle in discrete-time Kolmogorov systems by using average Liapunov functions. The exclusion principle shows that a weakly dominant species with a convex logarithmic growth rate function eliminates species with concave logarithmic growth rate functions. A general result is applied to specific population models. This application gives an improved exclusion principle for the specific population models.
10.
汪巍 《数学的实践与认识》2004,34(3):103-109
首先引入了差分系统基于两种度量的极端稳定性概念 ,然后建立了一些关于差分系统 ( h0 ,h)极端稳定性 (极端一致稳定性 ,极端渐近稳定性 ,极端一致渐近稳定性 )的判定准则 .在所得到的定理中 ,对△ V的限制较弱 ,特别地 ,△V甚至可以恒为正 ,从而便于实际应用 . 相似文献