全文获取类型
收费全文 | 10913篇 |
免费 | 868篇 |
国内免费 | 320篇 |
专业分类
化学 | 1397篇 |
晶体学 | 73篇 |
力学 | 2375篇 |
综合类 | 85篇 |
数学 | 3685篇 |
物理学 | 4486篇 |
出版年
2024年 | 13篇 |
2023年 | 57篇 |
2022年 | 168篇 |
2021年 | 197篇 |
2020年 | 219篇 |
2019年 | 183篇 |
2018年 | 159篇 |
2017年 | 226篇 |
2016年 | 298篇 |
2015年 | 224篇 |
2014年 | 416篇 |
2013年 | 722篇 |
2012年 | 403篇 |
2011年 | 493篇 |
2010年 | 413篇 |
2009年 | 630篇 |
2008年 | 663篇 |
2007年 | 712篇 |
2006年 | 667篇 |
2005年 | 542篇 |
2004年 | 421篇 |
2003年 | 472篇 |
2002年 | 449篇 |
2001年 | 394篇 |
2000年 | 456篇 |
1999年 | 337篇 |
1998年 | 401篇 |
1997年 | 242篇 |
1996年 | 186篇 |
1995年 | 168篇 |
1994年 | 135篇 |
1993年 | 139篇 |
1992年 | 149篇 |
1991年 | 106篇 |
1990年 | 92篇 |
1989年 | 57篇 |
1988年 | 69篇 |
1987年 | 64篇 |
1986年 | 52篇 |
1985年 | 77篇 |
1984年 | 55篇 |
1983年 | 23篇 |
1982年 | 34篇 |
1981年 | 23篇 |
1980年 | 18篇 |
1979年 | 27篇 |
1978年 | 12篇 |
1977年 | 10篇 |
1976年 | 10篇 |
1973年 | 6篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
Tamotsu Kohyama 《Journal of statistical physics》1991,63(3-4):637-651
A class of simple two-dimensional cellular automata with particle conservation is proposed for easy simulations of interacting particle systems. The automata are defined by the exchange of states of neighboring cells, depending on the configurations around the cells. By attributing an energy to a configuration of cells, we can select significant rules from the huge number of possible rules and classify them into several groups, based on the analogy with a binary alloy. By numerical calculations, cluster growth is found in two kinds of phases which reveal gas-solid coexistence and liquid droplets. Normalized scaling functions are obtained, and dynamical scaling is examined. 相似文献
102.
M. Maamache S. Menouar L. Krache 《International Journal of Theoretical Physics》2006,45(11):2191-2198
By using the Lewis-Riesenfeld theory and algebraic method, we present an alternative approach to obtain the exact solution of time-dependent Hamiltonian systems involving quadratic, inverse quadratic and (1/x)p+p(1/x) terms. This solution is discussed and compared with that obtained by Choi, J. R. (2003). International Journal of Theoretical Physics
42, 853].
PACS: 03.65Ge; 03.65Fd; 03.65Bz 相似文献
103.
F.J. Olmo A. Quirantes A. Alcntara H. Lyamani L. Alados-Arboledas 《Journal of Quantitative Spectroscopy & Radiative Transfer》2006,100(1-3):305-314
There is experimental evidence that the non-sphericity of certain atmospheric particles can cause scattering properties different from those predicted by standard Mie theory. Numerous studies indicate the need to consider the presence of non-spherical particles in modeling the optical properties of atmospheric aerosols. On the other hand, natural aerosols show a great variety of shapes, making difficult a realistic choice of a particle shape (or shape mixture) model. In this paper, we test a parameterization of the particle shape in the retrieval of size distribution, phase function, single scattering albedo and asymmetry parameter from direct and sky-radiance measurements. For this purpose we have substituted the Kernel based on the Mie theory included in the model SKYRAD.PACK by one derived for non-spherical particles. The method is applied under different atmospheric conditions, including Saharan dust outbreak, polluted and local mineral episodes. We compare the results with those obtained by the well known spheroids algorithm used in the AERONET network. 相似文献
104.
The critical limit of the eight-vertex model eigenvectors obtained by means of the generalized Bethe Ansatz is shown to give the six-vertex eigenvectors as constructed in a previous paper by two of the authors. Furthermore, an explicit mapping is established between these eigenvectors and the usual Bethe Ansatz eigenvectors of the six-vertex model. This allows one to show that the indexv labeling the eight-vertex eigenstates becomes exactly the third component of the total spin in the critical limit. 相似文献
105.
106.
It has already been argued that a classical (three-dimensional) Coulomb fluid confined between two parallel walls exhibits ideal gas features when the distance between the walls becomes small; this is confirmed in the present paper. Two-dimensional models of Coulomb fluids (with a logarithmic interaction), confined in a strip, are also studied. These models do not become ideal gases in the narrow strip limit. The correlation functions are also studied. There is a special temperature at which exact results are obtained. At that temperature, the two-dimensional, two-component plasma (two-dimensional Coulomb gas), which is a conductor when unconfined, becomes a dielectric as soon as it is confined in a strip of noninfinite width. This can be understood as a displacement of the Kosterlitz-Thouless transition by the confinement. 相似文献
107.
动态模糊随机信息处理的数学方法 总被引:1,自引:1,他引:0
本文系统地概述了我们近年来提出的动态模糊随机信息处理的数学方法,内容包括模糊随机变量、模糊随机过程和模糊随机微分方程的基本解法等方面的基本概念、基本定义和某些重要的定理,以及动态系统的模糊随机响应与可靠性分析的方法等。这些方法是为我们研究工程实际问题的需要逐步发展起来的,对于处理某些类型的问题简便实用。 相似文献
108.
109.
Ajay K. Saini Clifford M. Carlin Howard H. Patterson 《Journal of polymer science. Part A, Polymer chemistry》1992,30(3):419-427
New model compounds for poly[N,N′-bis(phenoxyphenyl)pyromellitimide] have been synthesized in order to investigate the formation of imine bonds which are proposed to form during the curing process and lead to crosslinking in the bulk polymer. Raman studies show that terminal amines can react with imide carbonyls during curing to form C?N bonds. The Raman band due to C?N appears at 1656 cm?1 and the band due to C?O closest to the imine bond is observed at 1742 cm?1. These results are in agreement with previously published results on vapor deposited polyimide films. 相似文献
110.
This paper introduces a profile empirical likelihood and a profile conditionally empirical likelihood to estimate the parameter
of interest in the presence of nuisance parameters respectively for the parametric and semiparametric models. It is proven
that these methods propose some efficient estimators of parameters of interest in the sense of least-favorable efficiency.
Particularly, for the decomposable semiparametric models, an explicit representation for the estimator of parameter of interest
is derived from the proposed nonparametric method. These new estimations are different from and more efficient than the existing
estimations. Some examples and simulation studies are given to illustrate the theoretical results.
The first author is supported by NNSF projects (10371059 and 10171051) of China. The second author is supported by a grant
from The Research Grants Council of the Hong Kong Special Administrative Region, China (#HKU7060/04P). The third author is
supported by the University Research Committee of the University of Hong Kong and a grant from the Research Grants Council
of the Hong Kong Special Administrative Region, China (Project No. HKU7323/01M). 相似文献