全文获取类型
收费全文 | 1110篇 |
免费 | 105篇 |
国内免费 | 74篇 |
专业分类
化学 | 442篇 |
晶体学 | 8篇 |
力学 | 36篇 |
综合类 | 8篇 |
数学 | 581篇 |
物理学 | 214篇 |
出版年
2024年 | 3篇 |
2023年 | 6篇 |
2022年 | 23篇 |
2021年 | 20篇 |
2020年 | 36篇 |
2019年 | 23篇 |
2018年 | 32篇 |
2017年 | 36篇 |
2016年 | 39篇 |
2015年 | 37篇 |
2014年 | 50篇 |
2013年 | 118篇 |
2012年 | 46篇 |
2011年 | 45篇 |
2010年 | 51篇 |
2009年 | 76篇 |
2008年 | 60篇 |
2007年 | 76篇 |
2006年 | 54篇 |
2005年 | 47篇 |
2004年 | 52篇 |
2003年 | 48篇 |
2002年 | 40篇 |
2001年 | 35篇 |
2000年 | 22篇 |
1999年 | 32篇 |
1998年 | 17篇 |
1997年 | 26篇 |
1996年 | 17篇 |
1995年 | 15篇 |
1994年 | 14篇 |
1993年 | 10篇 |
1992年 | 14篇 |
1991年 | 9篇 |
1990年 | 2篇 |
1989年 | 8篇 |
1988年 | 6篇 |
1987年 | 4篇 |
1986年 | 4篇 |
1985年 | 8篇 |
1984年 | 6篇 |
1983年 | 2篇 |
1982年 | 4篇 |
1980年 | 2篇 |
1979年 | 2篇 |
1978年 | 4篇 |
1977年 | 4篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1973年 | 1篇 |
排序方式: 共有1289条查询结果,搜索用时 15 毫秒
61.
D. Arnaudon N. Crampé A. Doikou L. Frappat É. Ragoucy J. Avan 《Czechoslovak Journal of Physics》2004,54(11):1153-1158
We consider open spin chains based on osp(M2n) Yangians and solve the reflection equations for some classes of reflection matrices, including the diagonal ones. Having then integrable open spin chains, we write the analytical Bethe Ansatz equations. More details and references can be found in D. Arnaudon et al.: Nucl. Phys B 668 (2003) 469 and 687 (2004) 257. 相似文献
62.
单分子电子器件的电子传输特性是当前分子电子学领域研究的热点.本文采用第一原理的ab inito法与格林函数方法,对Au电极-碳原子线-Au电极体系的电子结构以及电子传输等特性进行了分析,给出了C5、C10与C15原子线的电导 -电压曲线与伏安曲线.研究结果表明:碳原子线与Au电极之间的"接触"(结合)既有共价键的成分,又有离子键的成分;碳原子线的电导率及伏安特性具有特殊的量子效应和尺寸效应. 相似文献
63.
N. B. Yengibarian 《Journal of Theoretical Probability》2004,17(2):459-481
Existence of following factorization is proved:
Here A is a stochastic or semi-stochastic (substohastic) d×d matrix (d); I is the unit matrix; B and C are nonnegative, upper and lower triangular matrices. B is a semistochastic matrix; the diagonal entries of C are 1. An exact information on properties of matrices B and C are obtained in particular cases. Some results on existence of invariant distribution x for Markov chains in the cases of absence or presence of sources g of walking particles are obtained using the factorization (F). These problems described by homogeneous or nonhomogeneous equation (I–A)x=g. 相似文献
64.
Jeffrey S. Rosenthal 《Journal of Theoretical Probability》2003,16(3):671-688
We consider time-sampled Markov chain kernels, of the form P
=
n
n
P
n
. We prove bounds on the total variation distance to stationarity of such chains. We are motivated by the analysis of near-periodic MCMC algorithms. 相似文献
65.
This paper studies denumerable state continuous-time controlled Markov chains with the discounted reward criterion and a Borel action space. The reward and transition rates are unbounded, and the reward rates are allowed to take positive or negative values. First, we present new conditions for a nonhomogeneous Q(t)-process to be regular. Then, using these conditions, we give a new set of mild hypotheses that ensure the existence of -optimal (0) stationary policies. We also present a martingale characterization of an optimal stationary policy. Our results are illustrated with controlled birth and death processes. 相似文献
66.
Old and new from SOR 总被引:1,自引:0,他引:1
Wilhelm Niethammer 《Numerical Algorithms》2000,25(1-4):263-277
From the long history of Successive Over Relaxation (SOR) between the end of second world war and today three points are considered: (1) Classical results of Young and Varga are described. (2) It is shown how results on semiiterative methods can be used to derive these classical results in a unifying way and to compare SOR with other iterative methods. (3) In the last 15 years the application of SOR to compute the stationary distribution of a homogeneous Markov chain has been discussed. These results are reported, considering especially the term extended convergence introduced by Kontovasilis, Plemmons and Stewart. 相似文献
67.
Strong law of large numbers for Markov chains indexed by an infinite tree with uniformly bounded degree 总被引:3,自引:0,他引:3
In this paper,we study the strong law of large numbers and Shannon-McMillan (S-M) theorem for Markov chains indexed by an infinite tree with uniformly bounded degree.The results generalize the analogous results on a homogeneous tree. 相似文献
68.
Integrable systems underlying the Seiberg-Witten solutions for the N = 2 SQCD with gauge groups SO(n) and Sp(n) are proposed. They are described by the inhomogeneous XXX spin chain with specific boundary conditions given by reflection matrices. We attribute reflection matrices to orientifold planes in the brane construction and briefly discuss its possible deformations. 相似文献
69.
Karl Gustafson 《Linear algebra and its applications》2009,430(10):2705-907
A brief account of the conceptual formulation of the two entities in this paper’s title, plus an initial preliminary investigation of some of their mathematical properties, is given. 相似文献
70.
James Mc Laughlin Peter Zimmer 《Journal of Mathematical Analysis and Applications》2008,345(2):670-677
We prove a new Bailey-type transformation relating WP-Bailey pairs. We then use this transformation to derive a number of new 3- and 4-term transformation formulae between basic hypergeometric series. 相似文献