全文获取类型
收费全文 | 7731篇 |
免费 | 771篇 |
国内免费 | 668篇 |
专业分类
化学 | 816篇 |
晶体学 | 16篇 |
力学 | 892篇 |
综合类 | 191篇 |
数学 | 5805篇 |
物理学 | 1450篇 |
出版年
2024年 | 5篇 |
2023年 | 80篇 |
2022年 | 164篇 |
2021年 | 218篇 |
2020年 | 225篇 |
2019年 | 206篇 |
2018年 | 187篇 |
2017年 | 270篇 |
2016年 | 294篇 |
2015年 | 195篇 |
2014年 | 371篇 |
2013年 | 550篇 |
2012年 | 385篇 |
2011年 | 464篇 |
2010年 | 409篇 |
2009年 | 587篇 |
2008年 | 521篇 |
2007年 | 508篇 |
2006年 | 464篇 |
2005年 | 435篇 |
2004年 | 327篇 |
2003年 | 331篇 |
2002年 | 282篇 |
2001年 | 205篇 |
2000年 | 214篇 |
1999年 | 182篇 |
1998年 | 222篇 |
1997年 | 150篇 |
1996年 | 124篇 |
1995年 | 74篇 |
1994年 | 65篇 |
1993年 | 52篇 |
1992年 | 66篇 |
1991年 | 43篇 |
1990年 | 29篇 |
1989年 | 32篇 |
1988年 | 30篇 |
1987年 | 20篇 |
1986年 | 21篇 |
1985年 | 34篇 |
1984年 | 28篇 |
1983年 | 14篇 |
1982年 | 17篇 |
1981年 | 16篇 |
1980年 | 15篇 |
1979年 | 11篇 |
1978年 | 11篇 |
1975年 | 2篇 |
1974年 | 3篇 |
1972年 | 3篇 |
排序方式: 共有9170条查询结果,搜索用时 140 毫秒
111.
Systems that involve more than one decision maker are often optimized using the theory of games. In the traditional game theory, it is assumed that each player has a well-defined quantitative utility function over a set of the player decision space. Each player attempts to maximize/minimize his/her own expected utility and each is assumed to know the extensive game in full. At present, it cannot be claimed that the first assumption has been shown to be true in a wide variety of situations involving complex problems in economics, engineering, social and political sciences due to the difficulty inherent in defining an adequate utility function for each player in these types of problems. On the other hand, in many of such complex problems, each player has a heuristic knowledge of the desires of the other players and a heuristic knowledge of the control choices that they will make in order to meet their ends.In this paper, we utilize fuzzy set theory in order to incorporate the players' heuristic knowledge of decision making into the framework of conventional game theory or ordinal game theory. We define a new approach to N-person static fuzzy noncooperative games and develop a solution concept such as Nash for these types of games. We show that this general formulation of fuzzy noncooperative games can be applied to solve multidecision-making problems where no objective function is specified. The computational procedure is illustrated via application to a multiagent optimization problem dealing with the design and operation of future military operations. 相似文献
112.
利用第一类Chebyshev多项式的性质以及其与Lucas数的关系得到了关于Lucas数立方的一些恒等式. 相似文献
113.
Ioan Tomescu 《Journal of Graph Theory》2003,43(3):210-222
In the set of graphs of order n and chromatic number k the following partial order relation is defined. One says that a graph G is less than a graph H if ci(G) ≤ ci(H) holds for every i, k ≤ i ≤ n and at least one inequality is strict, where ci(G) denotes the number of i‐color partitions of G. In this paper the first ? n/2 ? levels of the diagram of the partially ordered set of connected 3‐chromatic graphs of order n are described. © 2003 Wiley Periodicals, Inc. J Graph Theory 43: 210–222, 2003 相似文献
114.
Frank N. Proske Madan L. Puri 《Proceedings of the American Mathematical Society》2003,131(9):2937-2944
In this article we prove a strong law of large numbers for Borel measurable nonseparably valued random elements in the case of generalized random sets.
115.
116.
Chen Yongnian 《模糊系统与数学》1995,(1)
ANTIFUZZYVECTORSPACES(Ⅱ)ChenYongnian(DepartmentofMathematics,XinjiangNormalUniversity,830054,Xinjiang,P.R.China)ANTIFUZZYVECT... 相似文献
117.
Dao-sheng Zheng 《计算数学(英文版)》1998,(2)
1.IntroductionSince1984,severalchinesemathematicianshaveobtailledmanyresultsboutmatrixoperatornormcondition.umbe.[ll'12'18].Twokindsmatrixconditionnllmbers[9]are:(1)IfAECoxsisnonsingular,thellunlberK.(A)~IIAll.llA--'if.iscalledtheor--normconditionnumberof… 相似文献
118.
Qiji J. Zhu 《Set-Valued Analysis》1998,6(2):171-185
Several different basic tools are used for studying subdifferentials. They are a nonlocal fuzzy sum rule in (Borwein et al., 1996; Zhu, 1996), a multidirectional mean value theorem in (Clarke and Ledyaev, 1994; Clarke et al., 1998), local fuzzy sum rules in (Ioffe, 1984, 1990) and an extremal principle in (Kruger and Mordukhovich, 1980; Mordukhovich, 1976, 1980, 1994). We show that all these basic results are equivalent and discuss some interesting consequences of this equivalence. 相似文献
119.
In a previous paper we considered an extension of the hard hexagon model to a solvable two-dimensional lattice gas with at most two particles per pair of adjacent sites. Here we use various mathematical identities (in particular Gordon's generalization of the Rogers-Ramanujan relations) to express the local densities in terms of elliptic functions. The critical behavior is then readily obtained.Supported in part by the National Science Foundation Grant MCS 8201733. 相似文献
120.
A layer of stratified combination composed of selected radiation shielding materials acquires better shielding property. Albedo
is used in such measurements as an integral measure ofγ-ray scattering. The stratified slabs of alternating heterogeneous layers have been found to have a virtual homogeneous property
with a definite effective atomic number. The angular distribution of back-scattered photons as well as the total number albedo
values for iron, aluminium and concrete in stratified combination for 662 keV and 1250 keV photons are reported. 相似文献