全文获取类型
收费全文 | 1468篇 |
免费 | 59篇 |
国内免费 | 246篇 |
专业分类
化学 | 415篇 |
晶体学 | 4篇 |
力学 | 33篇 |
综合类 | 9篇 |
数学 | 1136篇 |
物理学 | 176篇 |
出版年
2024年 | 2篇 |
2023年 | 29篇 |
2022年 | 29篇 |
2021年 | 25篇 |
2020年 | 26篇 |
2019年 | 45篇 |
2018年 | 37篇 |
2017年 | 40篇 |
2016年 | 23篇 |
2015年 | 32篇 |
2014年 | 73篇 |
2013年 | 134篇 |
2012年 | 77篇 |
2011年 | 62篇 |
2010年 | 67篇 |
2009年 | 103篇 |
2008年 | 111篇 |
2007年 | 112篇 |
2006年 | 92篇 |
2005年 | 68篇 |
2004年 | 83篇 |
2003年 | 65篇 |
2002年 | 49篇 |
2001年 | 41篇 |
2000年 | 45篇 |
1999年 | 37篇 |
1998年 | 45篇 |
1997年 | 31篇 |
1996年 | 33篇 |
1995年 | 22篇 |
1994年 | 20篇 |
1993年 | 15篇 |
1992年 | 14篇 |
1991年 | 8篇 |
1990年 | 7篇 |
1989年 | 3篇 |
1988年 | 9篇 |
1987年 | 4篇 |
1986年 | 8篇 |
1985年 | 7篇 |
1984年 | 7篇 |
1983年 | 4篇 |
1982年 | 5篇 |
1981年 | 4篇 |
1980年 | 2篇 |
1979年 | 2篇 |
1978年 | 8篇 |
1977年 | 3篇 |
1976年 | 3篇 |
1973年 | 1篇 |
排序方式: 共有1773条查询结果,搜索用时 0 毫秒
131.
J. Barral M. -O. Coppens B. B. Mandelbrot 《Journal de Mathématiques Pures et Appliquées》2003,82(12):1555-1589
A nonnegative 1-periodic multifractal measure on
is obtained as infinite random product of harmonics of a 1-periodic function W(t). Such infinite products are statistically self-affine and generalize certain Riesz products with random phases. They are martingale structures, therefore converge. The criterion on W for nondegeneracy is provided. It differs completely from those for other known random measures constructed as martingale limits of multiplicative processes. In particular, it is very sensitive to small changes in W(t). When these infinite products are interpreted in the framework of thermodynamic formalism for random transformations, logW is a potential function when W>0. For regular enough potentials, in case of degeneracy, the natural normalization makes the sequence of measures converge. Moreover, this normalization is neutral for nondegenerate martingales. The multifractal analysis of the limit martingale measure is performed for a class of potential functions having a dense countable set of jump points. 相似文献
132.
In this paper a comparison is made between two decomposition techniques to solve a staff scheduling problem with column generation.
In the first approach, decomposition takes place on the staff members, whereas in the second approach decomposition takes
place on the activities that have to be performed by the staff members. The resulting master LP is respectively a set partitioning
problem and a capacitated multi-commodity flow problem. Both approaches have been implemented in a branch-and-price algorithm.
We show a trade-off between modeling power and computation times of both techniques. 相似文献
133.
We show that the problem of searching for v-structures in a directed acyclic graph can be decomposed into searches in its decomposed subgraphs. This result simplifies the search for v-structures and the recovery of local causal relationships. 相似文献
134.
David E. Edmunds Bohumí r Opic 《Proceedings of the American Mathematical Society》2003,131(3):745-754
We give new characterizations of Lorentz spaces by means of certain quasi-norms which are shown to be equivalent to the classical ones.
135.
Björn Gustafsson Mihai Putinar 《Journal of Mathematical Analysis and Applications》2007,328(2):995-1006
The analytic continuation of the exponential transform of a domain in Rn is proved under some global geometric assumptions on the boundary. Two approximation schemes of the continued transform (one based on a Taylor series truncation, the other on a global eigenfunction expansion) are also discussed. 相似文献
136.
赵晓强 《应用数学学报(英文版)》1995,11(3):263-267
ONTHEEXISTENCEOFGLOBALGENERALSOLUTIONSOF POLYNOMIALSYSTEMSZHAOXIAOQIANG(赵晓强)(InstituteofAppliedMathematics,theChineseAcademyo... 相似文献
137.
Bundle-based decomposition for large-scale convex optimization: Error estimate and application to block-angular linear programs 总被引:3,自引:0,他引:3
Robinson has proposed the bundle-based decomposition algorithm to solve a class of structured large-scale convex optimization problems. In this method, the original problem is transformed (by dualization) to an unconstrained nonsmooth concave optimization problem which is in turn solved by using a modified bundle method. In this paper, we give a posteriori error estimates on the approximate primal optimal solution and on the duality gap. We describe implementation and present computational experience with a special case of this class of problems, namely, block-angular linear programming problems. We observe that the method is efficient in obtaining the approximate optimal solution and compares favorably with MINOS and an advanced implementation of the Dantzig—Wolfe decomposition method. 相似文献
138.
Liu Yongping 《数学年刊B辑(英文版)》1995,16(3):351-360
AVERAGE σ-K WIDTH OF CLASS OF L_p(R~n)IN L_q(R~n)AVERAGEσ-KWIDTHOFCLASSOFL_p(R~n)INL_q(R~n)¥LIUYONGPINGAbstract:Theaverageσ-Kwidt... 相似文献
139.
Hongmei Zhang Fawang Liu 《高等学校计算数学学报(英文版)》2007,16(2):181-192
In this paper, the space-time Riesz fractional partial differential equations with periodic conditions are considered. The equations are obtained from the integral partial differential equation by replacing the time derivative with a Caputo fractional derivative and the space derivative with Riesz potential. The fundamental solutions of the space Riesz fractional partial differential equation (SRFPDE) and the space-time Riesz fractional partial differential equation (STRFPDE) are discussed, respectively. Using methods of Fourier series expansion and Laplace transform, we derive the explicit expressions of the fundamental solutions for the SRFPDE and the STRFPDE, respectively. 相似文献
140.
对于带调速器的多台电机组,本文引入关联矩阵E=(e_(ij))_(n×n),应用李雅普诺夫函数分解法,研究了此电力大系统的暂态关联稳定性,得到了系统的分解系数与稳定区域的估计公式。 相似文献