全文获取类型
收费全文 | 7204篇 |
免费 | 874篇 |
国内免费 | 554篇 |
专业分类
化学 | 3111篇 |
晶体学 | 23篇 |
力学 | 637篇 |
综合类 | 111篇 |
数学 | 3990篇 |
物理学 | 760篇 |
出版年
2024年 | 7篇 |
2023年 | 73篇 |
2022年 | 58篇 |
2021年 | 95篇 |
2020年 | 212篇 |
2019年 | 196篇 |
2018年 | 195篇 |
2017年 | 193篇 |
2016年 | 303篇 |
2015年 | 268篇 |
2014年 | 338篇 |
2013年 | 558篇 |
2012年 | 377篇 |
2011年 | 429篇 |
2010年 | 401篇 |
2009年 | 460篇 |
2008年 | 490篇 |
2007年 | 476篇 |
2006年 | 436篇 |
2005年 | 372篇 |
2004年 | 350篇 |
2003年 | 380篇 |
2002年 | 307篇 |
2001年 | 205篇 |
2000年 | 202篇 |
1999年 | 194篇 |
1998年 | 155篇 |
1997年 | 212篇 |
1996年 | 106篇 |
1995年 | 78篇 |
1994年 | 67篇 |
1993年 | 64篇 |
1992年 | 58篇 |
1991年 | 52篇 |
1990年 | 34篇 |
1989年 | 21篇 |
1988年 | 21篇 |
1987年 | 25篇 |
1986年 | 25篇 |
1985年 | 22篇 |
1984年 | 14篇 |
1983年 | 10篇 |
1982年 | 14篇 |
1981年 | 8篇 |
1980年 | 12篇 |
1979年 | 12篇 |
1978年 | 6篇 |
1977年 | 11篇 |
1976年 | 13篇 |
1974年 | 5篇 |
排序方式: 共有8632条查询结果,搜索用时 0 毫秒
991.
Clara Löh 《Mathematische Zeitschrift》2006,253(1):197-218
Measure homology is a variation of singular homology designed by Thurston in his discussion of simplicial volume. Zastrow
and Hansen showed independently that singular homology (with real coefficients) and measure homology coincide algebraically
on the category of CW-complexes. It is the aim of this paper to prove that this isomorphism is isometric with respect to the ℓ1-seminorm on singular homology and the seminorm on measure homology induced by the total variation. This, in particular, implies
that one can calculate the simplicial volume via measure homology – as already claimed by Thurston. For example, measure homology
can be used to prove Gromov's proportionality principle of simplicial volume. 相似文献
992.
The time-optimal control of rigid-body angular rates is investigated in the absence of direct control over one of the angular velocity components. The existence of singular subarcs in the time-optimal trajectories is explored. A numerical survey of the optimality conditions reveals that, over a large range of boundary conditions, there are in general several distinct extremal solutions. A classification of extremal solutions is presented, and domains of existence of the extremal subfamilies are established in a reduced parameter space. A locus of Darboux points is obtained, and global optimality of the extremal solutions is observed in relation to the Darboux points. The continuous dependence of the optimal trajectories with respect to variations in control constraints is noted, and a procedure to obtain the time-optimal bang-bang solutions is presented.This work was supported in part by DARPA under Contract No. ACMP-F49620-87-C-0016, by SDIO/IST under Contract No. F49620-87-C0088, and by Air Force Grant AFOSR-89-0001. 相似文献
993.
邓少强 《数学物理学报(A辑)》2008,28(6):1218-1221
该文证明任何一个两点齐性的 Finsler 流形一定是黎曼流形. 证明过程中作者将泛函分析中经典的Mazur 定理推广到不一定是绝对齐次的 Minkowski 空间上. 相似文献
994.
Let G be a semisimple adjoint group over C and Ḡ be the De Concini–Procesi completion of G. In this paper, we define a Lagrangian subvariety Λ of the cotangent bundle of Ḡ such that the singular support of any character sheaf on Ḡ is contained in Λ.
Received: May 2006, Accepted: November 2006 相似文献
995.
We discuss the Schrödinger operator with positive singular perturbations given by operators which act in the space constructed by a positive measure supported by a null set. We construct examples when perturbations are given by the one-dimensional Laplacian on a segment. 相似文献
996.
广义对称正则长波方程的勒让德和切贝雪夫拟谱方法 总被引:3,自引:2,他引:1
本文考虑了具齐次边界条件的广义对称正则长波方程的Legendre和Chebyshev拟谱方法,构造了半离散和全离散的Legendre和Chebyshev拟谱格式,从理论上得到了这些格式对应的最优误差估计。 相似文献
997.
一类含参变量积分的常差分方程计算方法 总被引:1,自引:0,他引:1
梅宏 《数学的实践与认识》2007,37(9):184-189
首次利用常差分方程方法计算了一类形如∫0πa+co bs cnoxs xdx(n∈N,a,b∈R)的含非负整数参数n与实数a,b的积分,且得到了完整的积分公式. 相似文献
998.
999.
LIU Taishun & XU Qinghua Department of Mathematics Huzhou Teachers College Huzhou China Department of Mathematics Jiangxi Normal University Nanchang China 《中国科学A辑(英文版)》2006,(11)
In this paper, a class of biholomorphic mappings named quasi-convex mapping of order a in the unit ball of a complex Banach space is introduced. When the Banach space is confined to Cn, we obtain the relation between this class of mappings and the convex mappings. Furthermore, the growth and covering theorems of this class of mappings are given on the unit ball of a complex Banach space X. Finally, we get the second order terms coefficient estimations of the homogeneous expansion of quasi-convex mapping of order a defined on the polydisc in Cn and on the unit ball in a complex Banach space, respectively. 相似文献
1000.
GINDIKIN Simon 《中国科学A辑(英文版)》2006,49(11):1655-1661
We discuss some problems on rigidity of canonical realizations of complex homogeneous domains at ℂn
Dedicated to Professor Sheng GONG on the occasion of his 75th birthday 相似文献