全文获取类型
收费全文 | 21301篇 |
免费 | 2389篇 |
国内免费 | 2265篇 |
专业分类
化学 | 3144篇 |
晶体学 | 36篇 |
力学 | 1848篇 |
综合类 | 547篇 |
数学 | 14125篇 |
物理学 | 6255篇 |
出版年
2024年 | 26篇 |
2023年 | 171篇 |
2022年 | 344篇 |
2021年 | 409篇 |
2020年 | 453篇 |
2019年 | 455篇 |
2018年 | 480篇 |
2017年 | 625篇 |
2016年 | 726篇 |
2015年 | 565篇 |
2014年 | 1112篇 |
2013年 | 1378篇 |
2012年 | 1136篇 |
2011年 | 1349篇 |
2010年 | 1189篇 |
2009年 | 1484篇 |
2008年 | 1441篇 |
2007年 | 1525篇 |
2006年 | 1371篇 |
2005年 | 1317篇 |
2004年 | 1070篇 |
2003年 | 977篇 |
2002年 | 811篇 |
2001年 | 736篇 |
2000年 | 685篇 |
1999年 | 598篇 |
1998年 | 533篇 |
1997年 | 507篇 |
1996年 | 372篇 |
1995年 | 302篇 |
1994年 | 261篇 |
1993年 | 190篇 |
1992年 | 160篇 |
1991年 | 130篇 |
1990年 | 147篇 |
1989年 | 96篇 |
1988年 | 95篇 |
1987年 | 78篇 |
1986年 | 67篇 |
1985年 | 87篇 |
1984年 | 70篇 |
1983年 | 51篇 |
1982年 | 66篇 |
1981年 | 65篇 |
1980年 | 38篇 |
1979年 | 40篇 |
1978年 | 31篇 |
1977年 | 26篇 |
1976年 | 30篇 |
1973年 | 21篇 |
排序方式: 共有10000条查询结果,搜索用时 578 毫秒
151.
A. Truffert 《Annals of Operations Research》1991,30(1):115-156
The conditional expectation of integrands and random sets is the main tool of stochastic optimization. This work wishes to make up for the lack of real synthesis about this subject. We improve the existing hypothesis and simplify the corresponding proofs. In the convex case we especially study the problem of the exchange of conditional expectation and subdifferential operators. 相似文献
152.
B. Satco 《Journal of Mathematical Analysis and Applications》2007,332(2):919-933
Existence theorems and some properties of solutions set of three boundary value second order differential equations and inclusions in Banach spaces are obtained under Henstock, respectively Henstock-Kurzweil-Pettis integrability assumptions. Our results extend those obtained by Azzam, Castaing and Thibault in the Bochner integrability setting and in the Pettis integrability one. The continuity of the (unique) solution with respect to a parameter in the single-valued case is also studied. 相似文献
153.
Anna Avallone 《Mathematica Slovaca》2007,57(2):129-140
We prove the existence of separating points for every countable family of nonatomic σ-additive modular measures on a σ-complete lattice ordered effect algebra.
相似文献
154.
The paper addresses the problem of a semi-infinite plane crack along the interface between two isotropic half-spaces. Two methods of solution have been considered in the past: Lazarus and Leblond [1998a. Three-dimensional crack-face weight functions for the semi-infinite interface crack-I: variation of the stress intensity factors due to some small perturbation of the crack front. J. Mech. Phys. Solids 46, 489-511, 1998b. Three-dimensional crack-face weight functions for the semi-infinite interface crack-II: integrodifferential equations on the weight functions and resolution J. Mech. Phys. Solids 46, 513-536] applied the “special” method by Bueckner [1987. Weight functions and fundamental fields for the penny-shaped and the half-plane crack in three space. Int. J. Solids Struct. 23, 57-93] and found the expression of the variation of the stress intensity factors for a wavy crack without solving the complete elasticity problem; their solution is expressed in terms of the physical variables, and it involves five constants whose analytical representation was unknown; on the other hand, the “general” solution to the problem has been recently addressed by Bercial-Velez et al. [2005. High-order asymptotics and perturbation problems for 3D interfacial cracks. J. Mech. Phys. Solids 53, 1128-1162], using a Wiener-Hopf analysis and singular asymptotics near the crack front.The main goal of the present paper is to complete the solution to the problem by providing the connection between the two methods. This is done by constructing an integral representation for Lazarus-Leblond's weight functions and by deriving the closed form representations of Lazarus-Leblond's constants. 相似文献
155.
半连续格的刻画和映射 总被引:2,自引:0,他引:2
本文讨论了半连续格的一些性质,在半连续格中引入半Scott开集族,用半Scott开集族来刻画半连续格,同时定义了半连续格之间的半连续映射,得到闭包算子的像仍是半连续格的条件.最后,研究了半连续格上的半连续映射的全体不动点之集的性质。 相似文献
156.
高阶线性微分方程的解及其解的导数的不动点 总被引:2,自引:0,他引:2
研究了复域齐次和非齐次线性微分方程的解及其解的导数的不动点与超级问题,得到了整函数系数的齐次和非齐次线性微分方程的解及其解的导数的不动点的两个结果,所得结果推广了一些相关结果. 相似文献
157.
158.
JIN Lu 《数学年刊B辑(英文版)》2004,25(4):483-492
A unicity theorem concerning the total derivative for entire functions of several complex variables is proved. 相似文献
159.
In this paper, authors investigate the order of growth and the hyper order of solutions of a class of the higher order linear differential equation, and improve results of M. Ozawa^[6], G. Gundersen^[7] and J.K. Langley^[8], Li Chun-hong^[11]. 相似文献
160.
The theoretical investigation of the image states in front of an ultrathin iron film grown on copper has been performed by means of the embedding method and a recently developed procedure for the inclusion of the image potential tail in a first principle calculation. From the electronic response to an applied electric field, the image plane position has been evaluated. This also allows one to obtain useful information about the spin dependent screening properties of the system. Exchange splitting, effective mass, and lifetime of such surface states result in good agreement with recently performed two-photon photoemission experiments [see A.B. Schmidt, M. Pickel, M. Wiemhöfer, M. Donath, M. Weinelt, Phys. Rev. Lett. 95 (2005) 107402]. 相似文献