全文获取类型
收费全文 | 469249篇 |
免费 | 3840篇 |
国内免费 | 1113篇 |
专业分类
化学 | 238235篇 |
晶体学 | 7437篇 |
力学 | 21657篇 |
综合类 | 17篇 |
数学 | 62999篇 |
物理学 | 143857篇 |
出版年
2020年 | 3430篇 |
2019年 | 3854篇 |
2018年 | 11887篇 |
2017年 | 12549篇 |
2016年 | 10486篇 |
2015年 | 4929篇 |
2014年 | 6969篇 |
2013年 | 17487篇 |
2012年 | 16114篇 |
2011年 | 25488篇 |
2010年 | 16705篇 |
2009年 | 16757篇 |
2008年 | 22796篇 |
2007年 | 25748篇 |
2006年 | 13450篇 |
2005年 | 17408篇 |
2004年 | 13588篇 |
2003年 | 12812篇 |
2002年 | 10839篇 |
2001年 | 11264篇 |
2000年 | 8866篇 |
1999年 | 6584篇 |
1998年 | 5432篇 |
1997年 | 5425篇 |
1996年 | 5213篇 |
1995年 | 4560篇 |
1994年 | 4518篇 |
1993年 | 4394篇 |
1992年 | 5118篇 |
1991年 | 5089篇 |
1990年 | 4946篇 |
1989年 | 4989篇 |
1988年 | 4933篇 |
1987年 | 4912篇 |
1986年 | 4682篇 |
1985年 | 6037篇 |
1984年 | 6216篇 |
1983年 | 4942篇 |
1982年 | 5269篇 |
1981年 | 5212篇 |
1980年 | 4836篇 |
1979年 | 5360篇 |
1978年 | 5488篇 |
1977年 | 5505篇 |
1976年 | 5397篇 |
1975年 | 4979篇 |
1974年 | 4918篇 |
1973年 | 5032篇 |
1972年 | 3403篇 |
1967年 | 3314篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
We prove the existence of solutions to nonlinear free boundary problem with singularities at given points. 相似文献
992.
C. Sparber J. A. Carrillo J. Dolbeault P. A. Markowich 《Monatshefte für Mathematik》2004,141(3):237-257
We analyze the long-time behavior of transport equations for a class of dissipative quantum systems with Fokker-planck type diffusion operator, subject to confining potentials of harmonic oscillator type. We establish the existence and uniqueness of a non-equilibrium steady state for the corresponding dynamics. Further, using a (classical) convex Sobolev inequality, we prove an optimal exponential rate of decay towards this state and additionally give precise dispersion estimates in those cases, where no stationary state exists. 相似文献
993.
994.
A carousel is a dynamical system that describes the movement of an equilateral linkage in which the midpoint of each rod travels parallel to it. They are closely related to the floating body problem. We prove, using the work of Auerbach, that any figure that floats in equilibrium in every position is drawn by a carousel. Of special interest are such figures with rational perimetral density of the floating chords, which are then drawn by carousels. In particular, we prove that for some perimetral densities the only such figure is the circle, as the problem suggests. 相似文献
995.
996.
V E Krivonozhko O B Utkin A V Volodin I A Sablin M Patrin 《The Journal of the Operational Research Society》2004,55(10):1049-1058
The aim of the paper is to present and substantiate a technique to visualize DEA modelling results without any loss of mathematical rigour. The proposed family of parametric optimization methods allows one to construct an intersection of the multidimensional frontier with a two-dimensional plane determined by any pair of given directions. This approach reduces the efficiency analysis of production units to the investigation of well-known functions in economics. We also propose constructive methods to calculate marginal rates of substitution, marginal rates of transformation and so on. 相似文献
997.
998.
In this note we show how 1-factors in the middle two layers of the discrete cube can be used to construct 2-factors in the
Odd graph (the Kneser graph of (k − 1)-sets from a (2k − 1)-set). In particular, we use the lexical matchings of Kierstead and Trotter, and the modular matchings of Duffus, Kierstead
and Snevily, to give explicit constructions of two different 2-factorisations of the Odd graph.
This revised version was published online in September 2006 with corrections to the Cover Date. 相似文献
999.
A. Bourgeat O. Gipouloux E. Marui‐Paloka 《Mathematical Methods in the Applied Sciences》2004,27(4):381-403
In this paper, we study the global behaviour of an underground waste disposal in order to have an accurate upscaled model suitable for the computations involved in safety assessment processes. We start from a detailed model describing the transport of pollutant leaking from a high number of units. Using the method of homogenization, going to the limit, we obtain first a macroscopic model where the sources are now appearing globally. Then we compute a first‐order matched asymptotic expansion and we give the error estimates for this approximation. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
1000.
L. E. Payne P. W. Schaefer J. C. Song 《Mathematical Methods in the Applied Sciences》2004,27(17):2045-2053
Energy bounds are derived for Dirichlet type boundary value problems for the Navier–Stokes and Stokes equations when a combination of the solution values initially and at a later time is prescribed. The bounds are obtained by means of a differential inequality and imply uniqueness and continuous data dependence of the solutions for a range of values of the parameter in the non‐standard auxiliary condition. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献