全文获取类型
收费全文 | 3738篇 |
免费 | 638篇 |
国内免费 | 337篇 |
专业分类
化学 | 504篇 |
晶体学 | 88篇 |
力学 | 332篇 |
综合类 | 40篇 |
数学 | 1402篇 |
物理学 | 2347篇 |
出版年
2024年 | 5篇 |
2023年 | 33篇 |
2022年 | 103篇 |
2021年 | 74篇 |
2020年 | 99篇 |
2019年 | 88篇 |
2018年 | 85篇 |
2017年 | 81篇 |
2016年 | 97篇 |
2015年 | 90篇 |
2014年 | 170篇 |
2013年 | 287篇 |
2012年 | 167篇 |
2011年 | 166篇 |
2010年 | 181篇 |
2009年 | 243篇 |
2008年 | 236篇 |
2007年 | 242篇 |
2006年 | 219篇 |
2005年 | 211篇 |
2004年 | 171篇 |
2003年 | 175篇 |
2002年 | 215篇 |
2001年 | 158篇 |
2000年 | 154篇 |
1999年 | 150篇 |
1998年 | 134篇 |
1997年 | 102篇 |
1996年 | 64篇 |
1995年 | 66篇 |
1994年 | 59篇 |
1993年 | 40篇 |
1992年 | 36篇 |
1991年 | 33篇 |
1990年 | 23篇 |
1989年 | 26篇 |
1988年 | 28篇 |
1987年 | 25篇 |
1986年 | 29篇 |
1985年 | 30篇 |
1984年 | 17篇 |
1983年 | 9篇 |
1982年 | 20篇 |
1981年 | 12篇 |
1980年 | 6篇 |
1979年 | 8篇 |
1978年 | 10篇 |
1977年 | 11篇 |
1976年 | 12篇 |
1972年 | 4篇 |
排序方式: 共有4713条查询结果,搜索用时 250 毫秒
21.
This paper proposes a model for the parametric representation of linguistic hedges in Zadeh’s fuzzy logic. In this model each linguistic truth-value, which is generated from a primary term of the linguistic truth variable, is identified by a real number r depending on the primary term. It is shown that the model yields a method of efficiently computing linguistic truth expressions accompanied with a rich algebraic structure of the linguistic truth domain, namely De Morgan algebra. Also, a fuzzy logic based on the parametric representation of linguistic truth-values is introduced. 相似文献
22.
23.
WU Ke ZHAO Weizhong & GUO Hanying Department of Mathematics Capital Normal University Beijing China Institute of Theoretical Physics Chinese Academy of Sciences Beijing China 《中国科学A辑(英文版)》2006,(11)
In a way similar to the continuous case formally, we define in different but equivalent manners the difference discrete connection and curvature on discrete vector bundle over the regular lattice as base space. We deal with the difference operators as the discrete counterparts of the derivatives based upon the differential calculus on the lattice. One of the definitions can be extended to the case over the random lattice. We also discuss the relation between our approach and the lattice gauge theory and apply to the discrete integrable systems. 相似文献
24.
S. P. Popov 《Computational Mathematics and Mathematical Physics》2006,46(6):983-994
Numerical solutions to three systems of integrable evolutionary equations from the Toda lattice hierarchy are analyzed. These are the classical Toda lattice, the second local dispersive flow, and the second extended dispersive flow. Special attention is given to the properties of soliton solutions. For the equations of the second local flow, two types of solitons interacting in a special manner are found. Solutions corresponding to various initial data are qualitatively outlined. 相似文献
25.
关于PFI-代数与剩余格 总被引:10,自引:0,他引:10
本文提出了一种强FI代数-PFI代数,并且深入研究了它的性质,借此进一步揭示了FI-代数和剩余格之间更加密切的联系,进而以FI-代数为基本框架建立了R0-代数、正则剩余格等逻辑系统的结构特征(包括对隅结构)及其相互关系.这种以FI-代数为基础来统一处理剩余格和R0-代数的方法,同样适合于格蕴涵代数和MV代数等代数结构,而且从中更能清楚地看出它们之间的密切联系,也将有助于对相应形式逻辑系统与模糊推理的研究. 相似文献
26.
Let SB(X,Y) be the set of the bounded sublinear operators from a Banach space X into a Banach lattice Y. Consider π2(X,Y) the set of 2-summing sublinear operators. We study in this paper a variation of Grothendieck's theorem in the sublinear operators case. We prove under some conditions that every operator in SB(C(K),H) is in π2(C(K),H) for any compact K and any Hilbert H. In the noncommutative case the problem is still open. 相似文献
27.
Gábor Házi 《Central European Journal of Physics》2003,1(3):453-462
A general class of analytical solutions of the lattice Boltzmann equation is derived for two-dimensional, steady-state unidirectional
flows. A subset of the solutions that verifies the corresponding Navier-Stokes equations is given. It is pointed out that
this class includes, e.g., the Couette and the Poiseuille flow but not, e.g., the basic Kolmogorov flow. For steady-state
non-unidirectional flows, first and second order solutions of the lattice Boltzmann equation are derived. Practical consequences of the analysis
are mentioned. Differences between the technique applied here and those used in some earlier works are emphasized. 相似文献
28.
Marco Pretti 《Journal of statistical physics》2003,111(3-4):993-1015
In this article we deal with the variational approach to cactus trees (Husimi trees) and the more common recursive approach, that are in principle equivalent for finite systems. We discuss in detail the conditions under which the two methods are equivalent also in the analysis of infinite (self-similar) cactus trees, usually investigated to the purpose of approximating ordinary lattice systems. Such issue is hardly ever considered in the literature. We show (on significant test models) that the phase diagram and the thermodynamic quantities computed by the variational method, when they deviates from the exact bulk properties of the cactus system, generally provide a better approximation to the behavior of a corresponding ordinary system. Generalizing a property proved by Kikuchi, we also show that the numerical algorithm usually employed to perform the free energy minimization in the variational approach is always convergent. 相似文献
29.
In this paper a new definition of a lattice valued intuitionistic fuzzy set (LIFS) is introduced, in an attempt to overcome
the disadvantages of earlier definitions. Some properties of this kind of fuzzy sets and their basic operations are given.
The theorem of synthesis is proved: For every two families of subsets of a set satisfying certain conditions, there is an
lattice valued intuitionistic fuzzy set for which these are families of level sets.
The research supported by Serbian Ministry of Science and Technology, Grant No. 1227. 相似文献
30.