全文获取类型
收费全文 | 14733篇 |
免费 | 1696篇 |
国内免费 | 1418篇 |
专业分类
化学 | 431篇 |
晶体学 | 9篇 |
力学 | 1136篇 |
综合类 | 271篇 |
数学 | 12853篇 |
物理学 | 3147篇 |
出版年
2024年 | 28篇 |
2023年 | 186篇 |
2022年 | 210篇 |
2021年 | 293篇 |
2020年 | 489篇 |
2019年 | 513篇 |
2018年 | 485篇 |
2017年 | 548篇 |
2016年 | 545篇 |
2015年 | 365篇 |
2014年 | 749篇 |
2013年 | 1372篇 |
2012年 | 670篇 |
2011年 | 862篇 |
2010年 | 750篇 |
2009年 | 970篇 |
2008年 | 945篇 |
2007年 | 1032篇 |
2006年 | 867篇 |
2005年 | 780篇 |
2004年 | 690篇 |
2003年 | 692篇 |
2002年 | 611篇 |
2001年 | 439篇 |
2000年 | 480篇 |
1999年 | 444篇 |
1998年 | 372篇 |
1997年 | 310篇 |
1996年 | 243篇 |
1995年 | 128篇 |
1994年 | 124篇 |
1993年 | 82篇 |
1992年 | 83篇 |
1991年 | 77篇 |
1990年 | 42篇 |
1989年 | 34篇 |
1988年 | 33篇 |
1987年 | 26篇 |
1986年 | 17篇 |
1985年 | 37篇 |
1984年 | 44篇 |
1983年 | 26篇 |
1982年 | 34篇 |
1981年 | 27篇 |
1980年 | 22篇 |
1979年 | 17篇 |
1978年 | 14篇 |
1977年 | 11篇 |
1976年 | 7篇 |
1936年 | 7篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
91.
In this paper we characterize the local maxima of a continuous global optimization formulation for finding the independence
number of a graph. Classical Karush-Kuhn-Tucker conditions and simple combinatorial arguments are found sufficient to deduce
several interesting properties of the local and global maxima. These properties can be utilized in developing new approaches
to the maximum independent set problem. 相似文献
92.
Arne Barinka Stephan Dahlke Wolfgang Dahmen 《Advances in Computational Mathematics》2006,24(1-4):5-34
Recently adaptive wavelet methods have been developed which can be shown to exhibit an asymptotically optimal accuracy/work
balance for a wide class of variational problems including classical elliptic boundary value problems, boundary integral equations
as well as certain classes of noncoercive problems such as saddle point problems. A core ingredient of these schemes is the
approximate application of the involved operators in standard wavelet representation. Optimal computational complexity could
be shown under the assumption that the entries in properly compressed standard representations are known or computable in
average at unit cost. In this paper we propose concrete computational strategies and show under which circumstances this assumption
is justified in the context of elliptic boundary value problems.
Dedicated to Charles A. Micchelli on the occasion of his 60th birthday
Mathematics subject classifications (2000) 41A25, 41A46, 65F99, 65N12, 65N55.
This work has been supported in part by the Deutsche Forschungsgemeinschaft SFB 401, the first and third author are supported
in part by the European Community's Human Potential Programme under contract HPRN-CT-202-00286 (BREAKING COMPLEXITY). The
second author acknowledges the financial support provided through the European Union's Human Potential Programme, under contract
HPRN-CT-2002-00285 (HASSIP) and through DFG grant DA 360/4–1. 相似文献
93.
In this paper, we are concerned with the problem of stabilization for autonomous dynamical systems. We use theories in Liapunov stability and Lasalle stability theory and show that system (H) is stabilizable. 相似文献
94.
对G.Ladas的一个开问题的解答 总被引:3,自引:0,他引:3
本文获得了一个高阶非线性差分方程具有无界正解的充分条件,所得结果解决了G.Ladas提出的一个开问题。 相似文献
95.
96.
C. R. Bector S. Chandra M. K. Bector 《Journal of Optimization Theory and Applications》1989,60(2):243-260
Using a parametric approach, duality is presented for a minimax fractional programming problem that involves several ratios in the objective function.The first author is thankful to Natural Science and Engineering Research Council of Canada for financial support through Grant A-5319, and the authors are thankful to the anonymous referees for useful suggestions. 相似文献
97.
Successive column correction algorithms for solving sparse nonlinear systems of equations 总被引:1,自引:0,他引:1
Guangye Li 《Mathematical Programming》1989,43(1-3):187-207
This paper presents two algorithms for solving sparse nonlinear systems of equations: the CM-successive column correction algorithm and a modified CM-successive column correction algorithm. Aq-superlinear convergence theorem and anr-convergence order estimate are given for both algorithms. Some numerical results and the detailed comparisons with some previously established algorithms show that the new algorithms have some promise of being very effective in practice.This research was partially supported by contracts and grants: DOE DE-AS05-82ER1-13016, AFOSR 85-0243 at Rice University, Houston, U.S.A. and Natural Sciences and Engineering Research Council of Canada grant A-8639. 相似文献
98.
Some Results behind Dividend Problems 总被引:1,自引:0,他引:1
Ming Zhou Li Wei Jun-yi Guo 《应用数学学报(英文版)》2006,22(4):681-686
We consider the basic dividend problem of the compound Poisson model with constant barrierstrategy.Some results concealed behind the dividend problem are made explicit in the present work.Differentmethods and some of which are firstly given in this paper.All these results presented certain direct relationshipbetween some important actuary variables in classical risk theory is also revealed. 相似文献
99.
椭圆型问题一类广义差分法的L~2模误差估计 总被引:1,自引:0,他引:1
1.引 言 广义差分法作为处理偏微分方程的离散技术,能够保持质量,动量,能量等物理量的守恒.广义差分法(有些文献称为box method[3];finite volume element method[4],[5],[6])利用在对偶剖分体积单元积分原始方程,并将近似解限制于某一有限元空间而得到离散方程.因此,它在局部区域保持了原始方程的物理守恒性和其他重要特性.从而被广泛地应用于数值求解数学物理方程,特别是计算流体力学和热传导问题[11]. 对广义差分法的研究已有许多文献,专著[10]有详细的介绍.早期的工作主要考虑标准的重心对偶剖分.近年来Cai et,al[4],[5],[6],在某些假定下对较一般的对偶剖分给出了能量模误差估计,Huang and Xi[9]去掉了文献[6]中的这些限制.Chou,Li[8]和Li, 相似文献
100.
CRT显示器稳定性实验研究 总被引:4,自引:1,他引:3
用屏幕色度计对一台SONY-G520显示器的显色特性进行了测量,研究了其开机稳定性和短、中、长期内的色差及色度偏差。实验结果表明,开机后,显示器的亮度Y和色度x,y分别可在2h,30min和1h达到相对稳定状态,且在达到相对稳定后,在短、中、长期内的平均色差分别为0.0611,0.1469和1.2536CIELAB色差单位;在中期内,Y,x,y,L,a,b的平均偏差分别为0.0663,0.0008,0.0015,0.0695,0.4740和0.1766。通过对显示器稳定性的测量,为在对比度敏感测量和色貌模型、图像质量、图像感知模型评价等研究领域中用显示器进行实验研究奠定了基础。 相似文献