全文获取类型
收费全文 | 25976篇 |
免费 | 1518篇 |
国内免费 | 1138篇 |
专业分类
化学 | 9613篇 |
晶体学 | 89篇 |
力学 | 180篇 |
综合类 | 56篇 |
数学 | 16892篇 |
物理学 | 1802篇 |
出版年
2024年 | 33篇 |
2023年 | 298篇 |
2022年 | 235篇 |
2021年 | 240篇 |
2020年 | 476篇 |
2019年 | 689篇 |
2018年 | 731篇 |
2017年 | 437篇 |
2016年 | 614篇 |
2015年 | 718篇 |
2014年 | 1107篇 |
2013年 | 1987篇 |
2012年 | 1121篇 |
2011年 | 1638篇 |
2010年 | 1349篇 |
2009年 | 1631篇 |
2008年 | 1847篇 |
2007年 | 1792篇 |
2006年 | 1346篇 |
2005年 | 987篇 |
2004年 | 858篇 |
2003年 | 782篇 |
2002年 | 643篇 |
2001年 | 511篇 |
2000年 | 490篇 |
1999年 | 586篇 |
1998年 | 518篇 |
1997年 | 391篇 |
1996年 | 452篇 |
1995年 | 504篇 |
1994年 | 451篇 |
1993年 | 372篇 |
1992年 | 350篇 |
1991年 | 227篇 |
1990年 | 205篇 |
1989年 | 206篇 |
1988年 | 145篇 |
1987年 | 144篇 |
1986年 | 133篇 |
1985年 | 208篇 |
1984年 | 187篇 |
1983年 | 96篇 |
1982年 | 183篇 |
1981年 | 168篇 |
1980年 | 104篇 |
1979年 | 89篇 |
1978年 | 111篇 |
1977年 | 82篇 |
1976年 | 72篇 |
1975年 | 29篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
C. Foias A. E. Frazho I. Gohberg M. A. Kaashoek 《Integral Equations and Operator Theory》1997,29(4):455-490
The family of all solutions of the three chains completion problem with a prescribed tolerance is described explicitly. It is shown that this family can be parameterized by a natural set of contractive upper triangular operators. As an application all solutions to a suboptimal nonstationary Nehari problem are described. 相似文献
92.
93.
By exploiting the construction of charged field algebras as canonical extensions of CCR current algebras in 1+1 dimensions and nonregular representations of extended algebras, we provide an algebraic construction of local Fermi fields as ultrastrong limits of bosonic variables in all representations which are locally Fock with respect to the ground-state representation of the massless scalar field. 相似文献
94.
R. M. Dudley 《Probability Theory and Related Fields》1994,100(2):175-189
Summary In a separable metric space, if two Borel probability measures (laws) are nearby in a suitable metric, then there exist random variables with those laws which are nearby in probability. Specifically, by a well-known theorem of Strassen, the Prohorov distance between two laws is the infimum of Ky Fan distances of random variables with those laws. The present paper considers possible extensions of Strassen's theorem to two random elements one of which may be (compact) set-valued and/or non-measurable. There are positive results in finite-dimensional spaces, but with factors depending on the dimension. Examples show that such factors cannot entirely be avoided, so that the extension of Strassen's theorem to the present situation fails in infinite dimensions.This research was partially supported by a Guggenheim Fellowship, by National Science Foundation grant DMS 8505550 at MSRI-Berkeley, and other NSF grants 相似文献
95.
Ken Ono 《Mathematische Annalen》1998,312(2):251-260
96.
Dmitrii S. Silvestrov 《Acta Appl Math》1994,34(1-2):109-124
Coupling procedures for Markov renewal processes are described. Applications to ergodic theorems for processes with semi-Markov switchings are considered.This paper was partly prepared with the support of NFR Grant F-UP 10257-300. 相似文献
97.
Asymptotics in the random assignment problem 总被引:1,自引:0,他引:1
David Aldous 《Probability Theory and Related Fields》1992,93(4):507-534
Summary We show that, in the usual probabilistic model for the random assignment problem, the optimal cost tends to a limit constant in probability and in expectation. The method involves construction of an infinite limit structure, in terms of which the limit constant is defined. But we cannot improve on the known numerical bounds for the limit.Research supported by NSF Grant MCS90-01710 相似文献
98.
Non-local approximation of the Mumford-Shah functional 总被引:3,自引:0,他引:3
The Mumford-Shah functional, introduced to study image segmentation problems, is approximated in the sense of -convergence by a sequence of non-local integral functionals.
Received June 6, 1996 / Accepted July 11, 1996 相似文献
99.
Yuri Borovskikh 《Acta Appl Math》1994,35(3):213-298
U-statistics in Banach spaces are considered and thoroughly investigated. The martingale structure, estimates of moments, the law of large numbers, the central limit theorem, the invariance principle, estimates of the rate of convergence, and large deviations are established 相似文献
100.
This paper presents an analytic approach to the construction cost of fringe-balanced binary search trees. In [7], Mahmoud used a bottom-up approach and an urn model of Pólya. The present method is top-down and uses differential equations and Hwang's quasi-power theorem to derive the asymptotic normality of the number of rotations needed to construct such afringe balanced search tree. We also obtain the exact expectation and variance with this method. Although Pólya's urn model is no longer needed, we also present an elegant analysis of it based on an operator calculus as in [4].This research was supported by the Austrian Research Society (FWF) under the project number P12599-MAT. 相似文献