全文获取类型
收费全文 | 9200篇 |
免费 | 446篇 |
国内免费 | 753篇 |
专业分类
化学 | 837篇 |
晶体学 | 9篇 |
力学 | 496篇 |
综合类 | 92篇 |
数学 | 7691篇 |
物理学 | 1274篇 |
出版年
2023年 | 99篇 |
2022年 | 91篇 |
2021年 | 112篇 |
2020年 | 184篇 |
2019年 | 194篇 |
2018年 | 225篇 |
2017年 | 235篇 |
2016年 | 266篇 |
2015年 | 180篇 |
2014年 | 353篇 |
2013年 | 652篇 |
2012年 | 368篇 |
2011年 | 381篇 |
2010年 | 350篇 |
2009年 | 524篇 |
2008年 | 631篇 |
2007年 | 579篇 |
2006年 | 554篇 |
2005年 | 502篇 |
2004年 | 348篇 |
2003年 | 431篇 |
2002年 | 394篇 |
2001年 | 296篇 |
2000年 | 324篇 |
1999年 | 305篇 |
1998年 | 242篇 |
1997年 | 258篇 |
1996年 | 151篇 |
1995年 | 133篇 |
1994年 | 116篇 |
1993年 | 80篇 |
1992年 | 70篇 |
1991年 | 64篇 |
1990年 | 72篇 |
1989年 | 56篇 |
1988年 | 57篇 |
1987年 | 42篇 |
1986年 | 38篇 |
1985年 | 52篇 |
1984年 | 66篇 |
1983年 | 21篇 |
1982年 | 37篇 |
1981年 | 35篇 |
1980年 | 34篇 |
1979年 | 28篇 |
1978年 | 32篇 |
1977年 | 38篇 |
1976年 | 25篇 |
1974年 | 16篇 |
1973年 | 16篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
41.
Let P(z) be a polynomial of degree n with complex coefficients and consider the n–th order linear differential operator P(D). We show that the equation P(D)f = 0 has the Hyers–Ulam stability, if and only if the equation P(z) = 0 has no pure imaginary solution. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
42.
In the present work we consider the problem of interpolating scattered data using radial basis functions (RBF). In general, it is well known that this leads to a discrete linear inverse problem that needs to be regularized in order to provide a meaningful solution. The work focuses on a metric-regularization approach, based on a new class of RBF, called anisotropic RBF. The work provides theoretical justifications for the regularization approach and it considers a suitable proposal for the metric, supporting it by numerical examples. 相似文献
43.
P. Q. Khanh 《Journal of Optimization Theory and Applications》1995,87(2):359-378
We prove the Kuhn-Tucker sufficient optimality condition, the Wolfe duality, and a modified Mond-Weir duality for vector optimization problems involving various types of invex-convexlike functions. The class of such functins contains many known generalized convex functions. As applications, we demonstrate that, under invex-convexlikeness assumptions, the Pontryagin maximum principle is a sufficient optimality condition for cooperative differential games. The Wolfe duality is established for these games.The author is indebted to the referees and Professor W. Stadler for valuable remarks and comments, which have been used to revise considerably the paper. 相似文献
44.
In this paper, we consider a queueing system in which there are two exponential servers, each having his own queue, and arriving
customers will join the shorter queue. Based on the results given in Flatto and McKean, we rewrite the formula for the probability
that there are exactlyk customers in each queue, wherek = 0, 1,…. This enables us to present an algorithm for computing these probabilities and then to find the joint distribution
of the queue lengths in the system. A program and numerical examples are given. 相似文献
45.
A PICARD TYPE THEOREM AND BLOCH LAW 总被引:9,自引:0,他引:9
Ye Yasheng 《数学年刊B辑(英文版)》1994,15(1):75-80
A PICARD TYPE THEOREM AND BLOCH LAW ¥YEYASHENGAbstract:Apicardtypetheoremisproved,andacounterexampleisgiventoshowthattheBolch... 相似文献
46.
M. Pappalardo 《Journal of Optimization Theory and Applications》1991,70(1):97-107
We prove a property of the Bouligand tangent cone to the epigraph (or to the graph) of a locally Lipschitz function. It is also shown how this result can be used in determining Dini sequences. Finally, some relationships between such a cone and Dini derivatives are provided. 相似文献
47.
HypersurfacewithConstantMainCurvatureSymmetricFunctions¥WuBaoqiang;SongHongzao(XuzhouTeachersCollege,221009)(HenanUniversity,... 相似文献
48.
尹传存 《数学物理学报(A辑)》1997,17(2):145-151
设中的角域.该文绘出了A上正调和函数的Martin表示,讨论了极小调和函数与条件Brown运动的一个0—1律之间的关系,并给出了A上极小调和函数的表现形式, 相似文献
49.
We provide some inequalities and integral inequalities connected to the Jensen-Hadamard inequalities for convex functions.
In particular, we give some refinements to these inequalities. Some natural applications and further extensions are given.
Sunto Forniamo alcune diseguaglianze e diseguaglianze integrali connesse alle dise-gueglianze di Jensen-Hadamard per funzioni convesse. In particolare, diamo qualche miglioramento di queste diseguaglianze. Alcune applicazioni naturali ed ulteriori estensioni sono date.相似文献
50.
Charles Blair 《Mathematical Programming》1995,71(2):127-136
We identify a class of formulas computable in polynomial time such that the functions defined by these formulas are precisely the value functions of mixed-integer programs with rational constraint coefficients. 相似文献