全文获取类型
收费全文 | 1728篇 |
免费 | 343篇 |
国内免费 | 256篇 |
专业分类
化学 | 84篇 |
晶体学 | 7篇 |
力学 | 52篇 |
综合类 | 122篇 |
数学 | 1609篇 |
物理学 | 453篇 |
出版年
2024年 | 11篇 |
2023年 | 26篇 |
2022年 | 25篇 |
2021年 | 24篇 |
2020年 | 24篇 |
2019年 | 30篇 |
2018年 | 13篇 |
2017年 | 39篇 |
2016年 | 39篇 |
2015年 | 55篇 |
2014年 | 131篇 |
2013年 | 98篇 |
2012年 | 105篇 |
2011年 | 131篇 |
2010年 | 106篇 |
2009年 | 94篇 |
2008年 | 152篇 |
2007年 | 115篇 |
2006年 | 94篇 |
2005年 | 90篇 |
2004年 | 78篇 |
2003年 | 80篇 |
2002年 | 90篇 |
2001年 | 84篇 |
2000年 | 85篇 |
1999年 | 70篇 |
1998年 | 66篇 |
1997年 | 46篇 |
1996年 | 64篇 |
1995年 | 59篇 |
1994年 | 51篇 |
1993年 | 25篇 |
1992年 | 41篇 |
1991年 | 25篇 |
1990年 | 30篇 |
1989年 | 14篇 |
1988年 | 6篇 |
1987年 | 4篇 |
1986年 | 2篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1980年 | 1篇 |
1959年 | 1篇 |
排序方式: 共有2327条查询结果,搜索用时 15 毫秒
61.
Teng Xia Ju 《数学学报(英文版)》2009,25(5):831-844
In this paper, we show that if H is a finite-dimensional Hopf algebra such that H and H^* are semisimple, then gl.dim(A#σH)=gl.dim(A), where a is a convolution invertible cocycle. We also discuss the relationship of global dimensions between the crossed product A^#σH and the algebra A, where A is coacted by H. Dually, we give a sufficient condition for a finite dimensional coalgebra C and a finite dimensional semisimple Hopf algebra H such that gl.dim(C α H)=gl.dim(C). 相似文献
63.
In this article we show that the order of the point value, in the sense of Łojasiewicz, of a tempered distribution and the
order of summability of the pointwise Fourier inversion formula are closely related. Assuming that the order of the point
values and certain order of growth at infinity are given for a tempered distribution, we estimate the order of summability
of the Fourier inversion formula. For Fourier series, and in other cases, it is shown that if the distribution has a distributional
point value of order k, then its Fourier series is e.v. Cesàro summable to the distributional point value of order k+1. Conversely, we also show that if the pointwise Fourier inversion formula is e.v. Cesàro summable of order k, then the distribution is the (k+1)-th derivative of a locally integrable function, and the distribution has a distributional point value of order k+2. We also establish connections between orders of summability and local behavior for other Fourier inversion problems. 相似文献
64.
65.
针对多方给出评价指标集存在差异情形的方案筛选问题,提出了一种基于软集理论的方案筛选方法。在该方法中,首先依据各方给出关于备选方案符合评价指标要求的可接受水平,构建各方相应的评价指标子集,进而针对各备选方案符合评价指标要求的结果构建针对各方评价指标子集的软集;然后构建所有方案均符合全部指标要求的软集,进而通过各评价指标子集的软集与所有方案均符合全部指标要求的软集的积运算和算子运算,得到对应评价指标子集的每方可接受的备选方案集;进一步地,通过各方可接受的备选方案集间的并集运算及交集运算,可得到最终的方案筛选结果。最后,通过一个算例说明了本文给出方法的可行性和有效性。 相似文献
66.
Cluster synchronization in a network of non-identical dynamic systems is studied in this paper, using two-cluster synchronization for detailed analysis and discussion. The results show that the common intercluster coupling condition is not always needed for the diffusively coupled network. Several sufficient conditions are obtained by using the Schur unitary triangularization theorem, which extends previous results. Some numerical examples are presented for illustration. 相似文献
67.
This paper applies the exp-function method, which was originally proposed to find new exact travelling wave solutions of nonlinear evolution equations, to the Riccati equation, and some exact solutions of this equation are obtained. Based on the Riccati equation and its exact solutions, we find new and more generalvariable separation solutions with two arbitrary functions of (1+1)-dimensional coupled integrable dispersionless system. As some special examples, some new solutions can degenerate into variable separation solutions reported in open literatures. By choosing suitably two independent variables p(x) and q(t) inour solutions, the annihilation phenomena of the flat-basin soliton, arch-basin soliton, and flat-top soliton are discussed. 相似文献
68.
Within framework of zero curvature representation theory, a family of integrable rational semi-discrete systems is derived from a matrix spectral problem. The Hamiltonian forms of obtained semi-discrete systems are constructed by means of the discrete trace identity. The Liouville integrability for the obtained family is demonstrated. In the end, a reduced family of obtained semi-discrete systems and its Hamiltonian form are worked out. 相似文献
69.
In this paper, we extend a (2+2)-dimensional continuous zero curvature equation to (2+2)-dimensional discrete zero curvature equation, then a new (2+2)-dimensional cubic Volterra lattice hierarchy is obtained. Fhrthermore, the integrable coupling systems of the (2+2)-dimensional cubic Volterra lattice hierarchy and the generalized Toda lattice soliton equations are presented by using a Lie algebraic system sl(4). 相似文献
70.
The Hirota bilinear method for the coupled Burgers equation and the high-order Boussinesq–Burgers equation 下载免费PDF全文
This paper studies the coupled Burgers equation and the high-order Boussinesq–Burgers equation. The Hirota bilinear method is applied to show that the two equations are completely integrable. Multiple-kink (soliton) solutions and multiple-singular-kink (soliton) solutions are derived for the two equations. 相似文献