全文获取类型
收费全文 | 4776篇 |
免费 | 490篇 |
国内免费 | 346篇 |
专业分类
化学 | 539篇 |
晶体学 | 1篇 |
力学 | 787篇 |
综合类 | 47篇 |
数学 | 3036篇 |
物理学 | 1202篇 |
出版年
2024年 | 6篇 |
2023年 | 28篇 |
2022年 | 47篇 |
2021年 | 52篇 |
2020年 | 98篇 |
2019年 | 125篇 |
2018年 | 111篇 |
2017年 | 94篇 |
2016年 | 93篇 |
2015年 | 85篇 |
2014年 | 220篇 |
2013年 | 342篇 |
2012年 | 192篇 |
2011年 | 269篇 |
2010年 | 281篇 |
2009年 | 308篇 |
2008年 | 318篇 |
2007年 | 351篇 |
2006年 | 276篇 |
2005年 | 222篇 |
2004年 | 245篇 |
2003年 | 242篇 |
2002年 | 185篇 |
2001年 | 158篇 |
2000年 | 165篇 |
1999年 | 159篇 |
1998年 | 137篇 |
1997年 | 135篇 |
1996年 | 97篇 |
1995年 | 93篇 |
1994年 | 50篇 |
1993年 | 53篇 |
1992年 | 67篇 |
1991年 | 65篇 |
1990年 | 29篇 |
1989年 | 19篇 |
1988年 | 17篇 |
1987年 | 20篇 |
1986年 | 17篇 |
1985年 | 25篇 |
1984年 | 19篇 |
1983年 | 12篇 |
1982年 | 17篇 |
1981年 | 11篇 |
1980年 | 8篇 |
1979年 | 14篇 |
1978年 | 12篇 |
1977年 | 9篇 |
1976年 | 4篇 |
1974年 | 4篇 |
排序方式: 共有5612条查询结果,搜索用时 15 毫秒
61.
AO Sheng-Mei YAN Jia-Ren 《理论物理通讯》2007,47(1):15-18
Three types of expression in the dark-soliton perturbation theory based on squared Jost solutions are invesgigaged in ghis paper. It is shown that there are three formally different results about the effects of perturbagion on a dark soliton, and it is proved by means of a transformation between two integral variables that they are essentially equivalent. 相似文献
62.
L. V. Stepanova 《Journal of Applied Mechanics and Technical Physics》2008,49(1):142-147
This paper discusses the problem of finding the eigenvalue spectrum in determining the stress and strain fields at the tip
of an antiplane-shear crack in a power-law material. It is shown that the perturbation method provides an analytical dependence
of the eigenvalue on the material nonlinearity parameter and the eigenvalue of the linear problem. Thus, it is possible to
find the entire spectrum of eigenvalues and not only the eigenvalue of the Hutchinson-Rice-Rosengren problem.
__________
Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 49, No. 1, pp. 173–180, January–February, 2008. 相似文献
63.
ON OPTIMAL BACKWARD PERTURBATION ANALYSIS FOR THE LINEAR SYSTEM WITH BLOCK CYCLIC COEFFICIENT MATRIX
Based on the block style spectral decomposition, this paper deals with the optimal backward perturbation analysis for the linear system with block cyclic coefficient matrix. 相似文献
64.
We study a model linear convection-diffusion-reaction problem where both the diffusion term and the convection term are multiplied by small parameters εd and εc, respectively. Depending on the size of the parameters the solution of the problem may exhibit exponential layers at both end points of the domain. Sharp bounds for the derivatives of the solution are derived using a barrier-function technique. These bounds are applied in the analysis of a simple upwind-difference scheme on Shishkin meshes. This method is established to be almost first-order convergent, independently of the parameters εd and εc. 相似文献
65.
Non-compact generalized variational inequalities for quasi-monotone and hemi-continuous operators with applications 总被引:1,自引:0,他引:1
Some results are obtained for non-compact cases in topological vector spaces for the existence problem of solutions for some
set-valued variational inequalities with quasi-monotone and lower hemi-continuous operators, and with quasi-semi-monotone
and upper hemi-continuous operators. Some applications are given in non-reflexive Banach spaces for these existence problems
of solutions and for perturbation problems for these set-valued variational inequalities with quasi-monotone and quasi-semi-monotone
operators.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
66.
Yi Qin Thomas Trautmann 《Journal of Quantitative Spectroscopy & Radiative Transfer》2004,84(1):105-114
As a computationally effective tool, the first-order term of the radiative perturbation theory has been computed successfully, and has been applied in a number of areas. In this article, we develop the computational expressions for the higher-order terms of the perturbation expansion in a plane parallel atmosphere. These expressions are then implemented, and numerical results for some typical cases are presented. These results indicate that the computation is successful and that the higher-order terms are essential in cases where the first-order term alone cannot predict the perturbation with sufficient accuracy. 相似文献
67.
具有周期非均匀扰动的色散管理系统中的孤子传输 总被引:5,自引:1,他引:4
在准理想的色散管理系统中建立了非均匀扰动模型,研究了它们对孤子传输和相互作用的影响.这些扰动导致孤子崩塌,加剧了孤子间相互作用.它们影响的大小与周期长度和扰动强度有关,并且存在最坏周期长度和扰动共振现像.最后,引入非线性增益和滤波器来有效控制这些扰动的影响. 相似文献
68.
曼合布拜·热合木 《新疆大学学报(理工版)》2003,(1)
讨论了一类具有扩散率和 III类功能性反应的非自治捕食系统 ,证明了在适当条件下 ,系统是持久的 ,进一步如果系统是周期系统 ,则在一定条件下存在惟一全局稳定的周期解 . 相似文献
69.
70.
We propose a perturbation theory that allows solving the equations of motion for the displacement vector in the body of the Earth in the framework of the linear theory of elasticity. We show that tectonic processes are primarily determined by tidal actions. We analyze the tidal effects in the Earth–Moon–Sun system. 相似文献