全文获取类型
收费全文 | 12677篇 |
免费 | 1298篇 |
国内免费 | 1382篇 |
专业分类
化学 | 780篇 |
晶体学 | 17篇 |
力学 | 775篇 |
综合类 | 392篇 |
数学 | 11202篇 |
物理学 | 2191篇 |
出版年
2024年 | 16篇 |
2023年 | 126篇 |
2022年 | 147篇 |
2021年 | 265篇 |
2020年 | 240篇 |
2019年 | 283篇 |
2018年 | 260篇 |
2017年 | 370篇 |
2016年 | 423篇 |
2015年 | 298篇 |
2014年 | 632篇 |
2013年 | 823篇 |
2012年 | 554篇 |
2011年 | 748篇 |
2010年 | 696篇 |
2009年 | 899篇 |
2008年 | 935篇 |
2007年 | 1012篇 |
2006年 | 827篇 |
2005年 | 781篇 |
2004年 | 578篇 |
2003年 | 653篇 |
2002年 | 561篇 |
2001年 | 430篇 |
2000年 | 484篇 |
1999年 | 415篇 |
1998年 | 408篇 |
1997年 | 315篇 |
1996年 | 237篇 |
1995年 | 134篇 |
1994年 | 138篇 |
1993年 | 87篇 |
1992年 | 79篇 |
1991年 | 64篇 |
1990年 | 45篇 |
1989年 | 39篇 |
1988年 | 38篇 |
1987年 | 17篇 |
1986年 | 18篇 |
1985年 | 56篇 |
1984年 | 41篇 |
1983年 | 24篇 |
1982年 | 35篇 |
1981年 | 19篇 |
1980年 | 26篇 |
1979年 | 21篇 |
1978年 | 13篇 |
1977年 | 11篇 |
1976年 | 8篇 |
1936年 | 5篇 |
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
81.
In [W.-C. Kuo, C.C.A. Labuschagne, B.A. Watson, Discrete-time stochastic processes on Riesz spaces, Indag. Math. (N.S.) 15 (3) (2004) 435-451], we introduced the concepts of conditional expectations, martingales and stopping times on Riesz spaces. Here we formulate and prove order theoretic analogues of the Birkhoff, Hopf and Wiener ergodic theorems and the Strong Law of Large Numbers on Riesz spaces (vector lattices). 相似文献
82.
证明了在扩大的非标准模型中S-空间可完全表示Radon空间并讨论了S-空间的若干性质.还给出一个有限Borel测度空间为Radon空间的充要条件.最后证明了Radon空间的一个*-有限表示定理. 相似文献
83.
The object of the present investigation is to introduce a new trigonometric method of summation which is both regular and
Fourier effective and determine its status with reference to other methods of summation (see §2-§4) and also give an application
of this method to determine the degree of approximation in a new Banach space of functions conceived as a generalized Holder
metric (see §5). 相似文献
84.
The theory of Ribaucour transformations for hypersurfaces in space forms is established. For any such hypersurface M, that admits orthonormal principal vector fields, it was shown the existence of a totally umbilic hypersurface locally associated to M by a Ribaucour transformation. A method of obtaining linear Weingarten surfaces in a three-dimensional space form is provided. By applying the theory, a new one-parameter family of complete constant mean curvature (cmc) surfaces in the unit sphere, locally associated to the flat torus, is obtained. The family contains a class of complete cmc cylinders in the sphere. In particular, one gets a family of complete minimal surfaces and minimal cylinders, locally associated to the Clifford torus.Mathematics Subject Classifications (2000): 53C20. 相似文献
85.
Bernardo Lafuerza-Guillén Donal O’regan Reza Saadati 《Proceedings Mathematical Sciences》2007,117(1):61-70
We introduce the concept of quotient in PN spaces and give some examples. We prove some theorems with regard to the completeness
of a quotient. 相似文献
86.
Jian Ming ZHAN Bijan DAVVAZ K. P. SHUM 《数学学报(英文版)》2007,23(8):1345-1356
We describe the relationship between the fuzzy sets and the algebraic hyperstructures. In fact, this paper is a continuation of the ideas presented by Davvaz in (Fuzzy Sets Syst., 117: 477- 484, 2001) and Bhakat and Das in (Fuzzy Sets Syst., 80: 359-368, 1996). The concept of the quasicoincidence of a fuzzy interval value with an interval-valued fuzzy set is introduced and this is a natural generalization of the quasi-coincidence of a fuzzy point in fuzzy sets. By using this new idea, the concept of interval-valued (α,β)-fuzzy sub-hypermodules of a hypermodule is defined. This newly defined interval-valued (α,β)-fuzzy sub-hypermodule is a We shall study such fuzzy sub-hypermodules and sub-hypermodules of a hypermodule. generalization of the usual fuzzy sub-hypermodule. consider the implication-based interval-valued fuzzy 相似文献
87.
We prove equivalence of the definitions by the author and by Korevaar and Schoen of the Sobolev classes of mappings of a domain of an arithmetic n-dimensional space to a metric space. 相似文献
88.
T. Domínguez Benavides 《Journal of Mathematical Analysis and Applications》2004,291(1):100-108
Let X be a Banach space whose characteristic of noncompact convexity is less than 1 and satisfies the nonstrict Opial condition. Let C be a bounded closed convex subset of X, KC(X) the family of all compact convex subsets of X and T a nonexpansive mapping from C into KC(X) with bounded range. We prove that T has a fixed point. The nonstrict Opial condition can be removed if, in addition, T is an 1-χ-contractive mapping. 相似文献
89.
本文对几种模糊传递关系进行比较 ,从一个侧面说明了用于构造偏好关系的模糊关系应是互逆关系 .文中证明了对任意的 n阶互逆传递模糊关系 R,必有 Rn=Rn+1 . 相似文献
90.
On Covariant Phase Space and the Variational Bicomplex 总被引:1,自引:0,他引:1
Enrique G. Reyes 《International Journal of Theoretical Physics》2004,43(5):1267-1286
The notion of a phase space in classical mechanics is well known. The extension of this concept to field theory however, is a challenging endeavor, and over the years numerous proposals for such a generalization have appeared in the literature. In this paper We review a Hamiltonian formulation of Lagrangian field theory based on an extension to infinite dimensions of J.-M. Souriau's symplectic approach to mechanics. Following G. Zuckerman, we state our results in terms of the modern geometric theory of differential equations and the variational bicomplex. As an elementary example, we construct a phase space for the Monge–Ampere equation. 相似文献