全文获取类型
收费全文 | 2115篇 |
免费 | 322篇 |
国内免费 | 125篇 |
专业分类
化学 | 78篇 |
力学 | 299篇 |
综合类 | 35篇 |
数学 | 1326篇 |
物理学 | 824篇 |
出版年
2024年 | 4篇 |
2023年 | 20篇 |
2022年 | 30篇 |
2021年 | 27篇 |
2020年 | 46篇 |
2019年 | 51篇 |
2018年 | 42篇 |
2017年 | 75篇 |
2016年 | 66篇 |
2015年 | 60篇 |
2014年 | 85篇 |
2013年 | 194篇 |
2012年 | 92篇 |
2011年 | 90篇 |
2010年 | 90篇 |
2009年 | 110篇 |
2008年 | 141篇 |
2007年 | 140篇 |
2006年 | 152篇 |
2005年 | 138篇 |
2004年 | 106篇 |
2003年 | 102篇 |
2002年 | 79篇 |
2001年 | 79篇 |
2000年 | 73篇 |
1999年 | 53篇 |
1998年 | 55篇 |
1997年 | 47篇 |
1996年 | 40篇 |
1995年 | 33篇 |
1994年 | 26篇 |
1993年 | 26篇 |
1992年 | 27篇 |
1991年 | 20篇 |
1990年 | 19篇 |
1989年 | 17篇 |
1988年 | 11篇 |
1987年 | 9篇 |
1986年 | 11篇 |
1985年 | 14篇 |
1984年 | 7篇 |
1983年 | 3篇 |
1982年 | 13篇 |
1981年 | 11篇 |
1980年 | 5篇 |
1979年 | 7篇 |
1978年 | 5篇 |
1976年 | 3篇 |
1974年 | 2篇 |
1973年 | 2篇 |
排序方式: 共有2562条查询结果,搜索用时 15 毫秒
21.
How can the basic compatibility of theory and observations be investigated for nonlinear processes without requiring stochastic characterizations for residual error terms? The present paper proposes a flexible least-cost approach. For each possible estimatex for the sequence of process states, letc D (x) andx M(x) denote the costs incurred for deviations away from the prior dynamic specifications and prior measurement specifications, respectively. Define the cost-efficiency frontier to be the greatest lower bound for the set of all possible cost pairs [c D (x),c M(x)], conditional on the given observations. State sequence estimatesx that attain the cost-efficiency frontier indicate the possible ways that the actual process could have developed over time in a manner minimally incompatible with the prior dynamic and measurement specifications. An algorithm is developed for the exact sequential updating of the cost-efficient state sequence estimates as the duration of the process increases and additional observations are obtained. 相似文献
22.
Carsten Franz 《Proceedings of the American Mathematical Society》2006,134(8):2437-2446
A method to approximate the eigenvalues of linear operators depending on an unknown distribution is introduced and applied to weighted sums of squared normally distributed random variables. This area of application includes the approximation of the asymptotic null distribution of certain degenerated U- and V-statistics.
23.
P. -M. Binder 《Journal of statistical physics》1992,67(3-4):827-832
Average first-passage times for a single-variable stochastic model with a critical fixed point at the origin are computed by exact enumeration. The numerical measurements show excellent agreement with analytical results. The scaling function approaches the predicted asymptotic dependence. 相似文献
24.
两个非线性方程的准确解 总被引:3,自引:0,他引:3
借助于计算机代数系统Mathematica利用直接代数方法获得了两个有数学物理意义的非线性耗散-色散方程的准确解,这种方法也适用于高维非线性方程。 相似文献
25.
The sum of the largest eigenvalues of a symmetric matrix is a nonsmooth convex function of the matrix elements. Max characterizations for this sum are established, giving a concise characterization of the subdifferential in terms of a dual matrix. This leads to a very useful characterization of the generalized gradient of the following convex composite function: the sum of the largest eigenvalues of a smooth symmetric matrix-valued function of a set of real parameters. The dual matrix provides the information required to either verify first-order optimality conditions at a point or to generate a descent direction for the eigenvalue sum from that point, splitting a multiple eigenvalue if necessary. Connections with the classical literature on sums of eigenvalues and eigenvalue perturbation theory are discussed. Sums of the largest eigenvalues in the absolute value sense are also addressed.This paper is dedicated to Phil Wolfe on the occasion of his 65th birthday.The work of this author was supported by the National Science Foundation under grants CCR-8802408 and CCR-9101640.The work of this author was supported in part during a visit to Argonne National Laboratory by the Applied Mathematical Sciences subprogram of the Office of Energy Research of the U.S. Department of Energy under contract W-31-109-Eng-38, and in part during a visit to the Courant Institute by the U.S. Department of Energy under Contract DEFG0288ER25053. 相似文献
26.
Damien P. Foster Carlo Vanderzande Julia Yeomans 《Journal of statistical physics》1992,69(3-4):857-868
We study the zero-temperature behavior of several simple models for randomly self-interacting polymers in one and 1+1 dimensions. Results are based on exact enumeration and closed-form expressions. 相似文献
27.
28.
H. Stephani 《General Relativity and Gravitation》2003,35(3):467-474
An intuitive definition of standing gravitational waves is proposed. Some main classes of exact vacuum solutions are searched for standing gravitational waves, in most cases with a negative result. Only some Einstein–Rosen waves meet the conditions. 相似文献
29.
The paper analyzes new publications on the brittle fracture mechanics of prestressed materials. It is found out that new scientific results published in the International Journal of Solids and Structures in 2002 are a particular case of the results obtained at the Institute of Mechanics 20 years ago 相似文献
30.