全文获取类型
收费全文 | 9271篇 |
免费 | 1040篇 |
国内免费 | 596篇 |
专业分类
化学 | 2140篇 |
晶体学 | 120篇 |
力学 | 2690篇 |
综合类 | 62篇 |
数学 | 2283篇 |
物理学 | 3612篇 |
出版年
2024年 | 11篇 |
2023年 | 99篇 |
2022年 | 199篇 |
2021年 | 167篇 |
2020年 | 224篇 |
2019年 | 194篇 |
2018年 | 204篇 |
2017年 | 231篇 |
2016年 | 286篇 |
2015年 | 226篇 |
2014年 | 356篇 |
2013年 | 627篇 |
2012年 | 451篇 |
2011年 | 486篇 |
2010年 | 439篇 |
2009年 | 570篇 |
2008年 | 535篇 |
2007年 | 540篇 |
2006年 | 483篇 |
2005年 | 526篇 |
2004年 | 383篇 |
2003年 | 402篇 |
2002年 | 411篇 |
2001年 | 324篇 |
2000年 | 292篇 |
1999年 | 268篇 |
1998年 | 245篇 |
1997年 | 213篇 |
1996年 | 154篇 |
1995年 | 182篇 |
1994年 | 145篇 |
1993年 | 124篇 |
1992年 | 89篇 |
1991年 | 103篇 |
1990年 | 73篇 |
1989年 | 70篇 |
1988年 | 92篇 |
1987年 | 78篇 |
1986年 | 83篇 |
1985年 | 69篇 |
1984年 | 47篇 |
1983年 | 23篇 |
1982年 | 64篇 |
1981年 | 26篇 |
1980年 | 12篇 |
1979年 | 15篇 |
1978年 | 17篇 |
1977年 | 12篇 |
1976年 | 14篇 |
1971年 | 5篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
K. Y. Lin 《Journal of statistical physics》1987,49(1-2):269-279
The spontaneous magnetization of the Ising model on a 4–8 lattice with six different coupling constants and two different magnetic moments is studied. A formula for the spontaneous magnetization is proposed. The result agrees with the exact low-temperature series expansions up to the 12th order. 相似文献
12.
Second-order random wave solutions for interfacial internal waves in N-layer density-stratified fluid 下载免费PDF全文
This paper studies the random internal wave equations describing the density interface displacements and the velocity potentials of N-layer stratified fluid contained between two rigid walls at the top and bottom. The density interface displacements and the velocity potentials were solved to the second-order by an expansion approach used by Longuet-Higgins (1963) and Dean (1979) in the study of random surface waves and by Song (2004) in the study of second- order random wave solutions for internal waves in a two-layer fluid. The obtained results indicate that the first-order solutions are a linear superposition of many wave components with different amplitudes, wave numbers and frequencies, and that the amplitudes of first-order wave components with the same wave numbers and frequencies between the adjacent density interfaces are modulated by each other. They also show that the second-order solutions consist of two parts: the first one is the first-order solutions, and the second one is the solutions of the second-order asymptotic equations, which describe the second-order nonlinear modification and the second-order wave-wave interactions not only among the wave components on same density interfaces but also among the wave components between the adjacent density interfaces. Both the first-order and second-order solutions depend on the density and depth of each layer. It is also deduced that the results of the present work include those derived by Song (2004) for second-order random wave solutions for internal waves in a two-layer fluid as a particular case. 相似文献
13.
14.
Hugh Thomas 《Order》2006,23(2-3):249-269
In this paper, we study lattices that posess both the properties of being extremal (in the sense of Markowsky) and of being left modular (in the sense of Blass and Sagan). We call such lattices trim and show that they posess some additional appealing properties, analogous to those of a distributive lattice. For example, trimness is preserved under taking intervals and suitable sublattices. Trim lattices satisfy a weakened form of modularity. The order complex of a trim lattice is contractible or homotopic to a sphere; the latter holds exactly if the maximum element of the lattice is a join of atoms. Any distributive lattice is trim, but trim lattices need not be graded. The main example of ungraded trim lattices are the Tamari lattices and generalizations of them. We show that the Cambrian lattices in types A and B defined by Reading are trim; we conjecture that all Cambrian lattices are trim. 相似文献
15.
A. B. Mazo 《Fluid Dynamics》2002,37(6):913-918
Plane ideal incompressible flow in a rectangular channel partitioned by a thin permeable barrier (lattice) is considered. In flowing through the lattice the stream suddenly (jumpwise) changes direction and loses energy. The flow is assumed to be vortical; the vorticity is discontinuous on the lattice. A mathematical formulation of the problem for the stream function is proposed in the form of a nonlinear elliptic equation with coefficients discontinuous on the lattice line. A numerical solution is constructed using the finite-element iteration method. The results of the numerical simulation show how the flow velocity profile in the channel can be controlled by means of permeable barriers. 相似文献
16.
I. L. Davies K. E. Markides M. L. Lee M. W. Raynor K. D. Bartle 《Journal of separation science》1989,12(4):193-207
Although coupled liquid chromatographygas chromatography (LC-GC) was first demonstrated ten years ago, only in the last few years has there been a sudden surge of interest in the technique. Approximately 70% of the total number of LC-GC applications have been published in the last two years (1987–88) alone. This review categorizes LC-GC publications into four main application areas: fossil fuels, foods, environmental samples, biologiical/pharmaceutical samples, and miscellaneous samples. Multidimensional separations carried out using other coupled-column chromatographic techniques (such as supercritical fluid chromatography (SFC) with GC, and on-line trace enrichment-GC) have also been included in this review. 相似文献
17.
18.
We consider a system of multicolour disordered lattice gas, following closely the (monocolour) introduced by Faggionato and Martinelli(3,4). We study the projection on the monocolour system and we derive an estimate of the closeness between grand canonical and canonical Gibbs measures.
AMS Classification: Primary: 60K35, 82C20, 82C22 相似文献
19.
Mathematical economics has a long history and covers many interdisciplinary areas between mathematics and economics. At its center lies the theory of market equilibrium. The purpose of this expository article is to introduce mathematicians to price decentralization in general equilibrium theory. In particular, it concentrates on the role of positivity in the theory of convex economic analysis and the role of normal cones in the theory of non-convex economies. 相似文献
20.