全文获取类型
收费全文 | 4982篇 |
免费 | 420篇 |
国内免费 | 412篇 |
专业分类
化学 | 216篇 |
晶体学 | 3篇 |
力学 | 550篇 |
综合类 | 71篇 |
数学 | 3923篇 |
物理学 | 1051篇 |
出版年
2024年 | 10篇 |
2023年 | 57篇 |
2022年 | 76篇 |
2021年 | 75篇 |
2020年 | 127篇 |
2019年 | 133篇 |
2018年 | 155篇 |
2017年 | 149篇 |
2016年 | 180篇 |
2015年 | 122篇 |
2014年 | 267篇 |
2013年 | 447篇 |
2012年 | 219篇 |
2011年 | 312篇 |
2010年 | 269篇 |
2009年 | 275篇 |
2008年 | 345篇 |
2007年 | 309篇 |
2006年 | 282篇 |
2005年 | 259篇 |
2004年 | 215篇 |
2003年 | 209篇 |
2002年 | 202篇 |
2001年 | 160篇 |
2000年 | 161篇 |
1999年 | 150篇 |
1998年 | 140篇 |
1997年 | 96篇 |
1996年 | 76篇 |
1995年 | 59篇 |
1994年 | 50篇 |
1993年 | 31篇 |
1992年 | 21篇 |
1991年 | 17篇 |
1990年 | 30篇 |
1989年 | 19篇 |
1988年 | 18篇 |
1987年 | 10篇 |
1986年 | 10篇 |
1985年 | 13篇 |
1984年 | 13篇 |
1983年 | 3篇 |
1982年 | 11篇 |
1981年 | 7篇 |
1980年 | 4篇 |
1979年 | 6篇 |
1978年 | 4篇 |
1976年 | 3篇 |
1973年 | 3篇 |
1936年 | 2篇 |
排序方式: 共有5814条查询结果,搜索用时 15 毫秒
41.
A formulation of an implicit characteristic-flux-averaging method for the unsteady Euler equations with real gas effects is presented. Incorporation of a real gas into a general equation of state is achieved by considering the pressure as a function of density and specific internal energy. The Ricmann solver as well as the flux-split algorithm are modified by introducing the pressure derivatives with respect to density and internal energy. Expressions for calculating the values of the flow variables for a real gas at the cell faces are derived. The Jacobian matrices and the eigenvectors are defined for a general equation of state. The solution of the system of equations is obtained by using a mesh-sequencing method for acceleration of the convergence. Finally, a test case for a simple form of equation of state displays the differences from the corresponding solution for an ideal gas. 相似文献
42.
Semyon Alesker 《Geometric And Functional Analysis》2007,17(4):1321-1341
This is a non-technical survey of a recent theory of valuations on manifolds constructed in [A10], [A11], [AF] and [A12],
and actually a guide to this series of articles. We also review some recent related results obtained by a number of people.
Received: February 2006, Revision: June 2006, Accepted: June 2006 相似文献
43.
44.
Hans C. Fogedby 《Journal of statistical physics》1992,69(1-2):411-425
We elaborate in some detail on a new phase space approach to complexity, due to Y.-C. Zhang. We show in particular that the connection between maximal complexity and power law noise or correlations can be derived from a simple variational principle. For a 1D signal we find 1/f noise, in accordance with Zhang. 相似文献
45.
46.
王军秀 《纯粹数学与应用数学》2007,23(3):406-408
利用欧拉公式研究了Gdk图的平面性,获得了一个重要定理,并由此得到了关于平面图色数的一个结论. 相似文献
47.
We exhibit a characteristic structure of the class of all regular graphs of degree d that stems from the spectra of their adjacency matrices. The structure has a fractal threadlike appearance. Points with coordinates given by the mean and variance of the exponentials of graph eigenvalues cluster around a line segment that we call a filar. Zooming-in reveals that this cluster splits into smaller segments (filars) labeled by the number of triangles in graphs. Further zooming-in shows that the smaller filars split into subfilars labeled by the number of quadrangles in graphs, etc. We call this fractal structure, discovered in a numerical experiment, a multifilar structure. We also provide a mathematical explanation of this phenomenon based on the Ihara-Selberg trace formula, and compute the coordinates and slopes of all filars in terms of Bessel functions of the first kind. 相似文献
48.
49.
Various tests have been carried out in order to compare the performances of several methods used to solve the non-symmetric linear systems of equations arising from implicit discretizations of CFD problems, namely the scalar advection-diffusion equation and the compressible Euler equations. The iterative schemes under consideration belong to three families of algorithms: relaxation (Jacobi and Gauss-Seidel), gradient and Newton methods. Two gradient methods have been selected: a Krylov subspace iteration method (GMRES) and a non-symmetric extension of the conjugate gradient method (CGS). Finally, a quasi-Newton method has also been considered (Broyden). The aim of this paper is to provide indications of which appears to be the most adequate method according to the particular circumstances as well as to discuss the implementation aspects of each scheme. 相似文献
50.
For any given positive integer n≥1,the Euler functionφ(n) is defined to be the number of positive integers not exceeding n,which is relatively prime to n.ω(n) is defined to be the number of different prime divisors of n.In order to know the solvability of the function ofφ(φ(φ(n)))=2~(ω(n)),properties of the number theoretical functionφ(φ(n)) is studied in the paper. 相似文献