全文获取类型
收费全文 | 2956篇 |
免费 | 30篇 |
国内免费 | 53篇 |
专业分类
化学 | 106篇 |
力学 | 87篇 |
综合类 | 28篇 |
数学 | 2572篇 |
物理学 | 246篇 |
出版年
2024年 | 3篇 |
2023年 | 6篇 |
2022年 | 17篇 |
2021年 | 15篇 |
2020年 | 38篇 |
2019年 | 17篇 |
2018年 | 18篇 |
2017年 | 32篇 |
2016年 | 51篇 |
2015年 | 52篇 |
2014年 | 124篇 |
2013年 | 187篇 |
2012年 | 151篇 |
2011年 | 200篇 |
2010年 | 132篇 |
2009年 | 237篇 |
2008年 | 167篇 |
2007年 | 214篇 |
2006年 | 172篇 |
2005年 | 114篇 |
2004年 | 99篇 |
2003年 | 84篇 |
2002年 | 89篇 |
2001年 | 118篇 |
2000年 | 84篇 |
1999年 | 69篇 |
1998年 | 70篇 |
1997年 | 57篇 |
1996年 | 55篇 |
1995年 | 40篇 |
1994年 | 13篇 |
1993年 | 16篇 |
1992年 | 15篇 |
1991年 | 12篇 |
1990年 | 9篇 |
1989年 | 12篇 |
1988年 | 10篇 |
1987年 | 3篇 |
1986年 | 6篇 |
1985年 | 50篇 |
1984年 | 48篇 |
1983年 | 19篇 |
1982年 | 38篇 |
1981年 | 33篇 |
1980年 | 24篇 |
1979年 | 15篇 |
1978年 | 4篇 |
排序方式: 共有3039条查询结果,搜索用时 15 毫秒
91.
92.
本文讨论了F数的扩张加法和扩张数乘运算的性质;并举反例说明这样的扩张运.算不能使F数全体F*构成线性空间;最后对可列个F数的运算进行了讨论. 相似文献
93.
Azriel Rosenfeld 《Fuzzy Sets and Systems》1984,13(3):241-246
In pattern recognition one often wants to measure geometric properties of imprecisely defined subsets of an image. This paper proposes definitions of intrinsic and extrinsic diameter for fuzzy subsets which reduce to the ordinary definitions when the subsets are crisp. We also define height and width for a fuzzy subset and show how they relate to the area (i.e., integral of membership). For convex fuzzy subsets the intrinsic diameter cannot exceed the extrinsic diameter, but it can be smaller. Finally, for piecewise constant convex fuzzy subsets the intrinsic diameter cannot exceed half the fuzzy perimeter, but this need not be true in the nonconvex case. 相似文献
94.
Arne Pfeilsticker 《Fuzzy Sets and Systems》1981,6(3):209-233
Ideas are presented to show how fuzzy mathematics can be applied in macro-economics in combination with the systems approach in order to bridge the gap between mathematical and language-oriented economists.Two reasons are given.From a mathematical point of view, fuzzy sets, fuzzy relations and fuzzy logic are not fuzzy at all. They are all well defined, but tend to be more complicated than traditional, mathematical concepts used in economics.From a language-oriented economist's point of view, fuzzy sets, etc. are used to express mathematically the type of concepts which are typical in language and most valuable in dealing with complex systems like an economy.The paper deals with economics in general terms, but examples are provided to illustrate the ideas. 相似文献
95.
We apply the theory of fuzzy subsets to the multiple objective decision problem of stock selection. We allow our objectives to have varying degrees of importance. We discuss various criteria used in selecting stocks. We indicate some procedures for subjectively evaluating the membership functions associated with these criteria. 相似文献
96.
97.
P.E Kloeden 《Fuzzy Sets and Systems》1982,7(3):275-296
A fuzzy dynamical system on an underlying complete, locally compact metric state space X is defined axiomatically in terms of a fuzzy attainability set mapping on X. This definition includes as special cases crisp single and multivalued dynamical systems on X. It is shown that the support of such a fuzzy dynamical system on X is a crisp multivalued dynamical system on X, and that such a fuzzy dynamical system can be considered as a crisp dynamical system on a state space of nonempty compact fuzzy subsets of X. In addition fuzzy trajectories are defined, their existence established and various properties investigated. 相似文献
98.
Ákos Császár 《Journal of Mathematical Analysis and Applications》2004,297(2):490-494
The paper presents a formula for the γ-interior of a set under special conditions for , more general than those in the previous paper [Acta Math. Hungar. 80 (1998) 89-93]. There are also some applications. 相似文献
99.
Non-dual fuzzy connections 总被引:1,自引:0,他引:1
The lack of double negation and de Morgan properties makes fuzzy logic unsymmetrical. This is the reason why fuzzy versions of notions like closure operator or Galois connection deserve attention for both antiotone and isotone cases, these two cases not being dual. This paper offers them attention, comming to the following conclusions: – some kind of hardly describable local preduality still makes possible important parallel results; – interesting new concepts besides antitone and isotone ones (like, for instance, conjugated pair), that were classically reducible to the first, gain independency in fuzzy setting. 相似文献
100.
In this paper, we introduce and study the signed fuzzy-valued measure and using the representation theorem of fuzzy numbers, we establish the Radon-Nikodym theorem for fuzzy-valued measurable functions with respect to fuzzy-valued measures.AMS Subject Classification (2000): 28E10, 04A72The research of this work is supposed by a grant of the education committee of Liaoning Province, China #20161049 相似文献