全文获取类型
收费全文 | 1461篇 |
免费 | 106篇 |
国内免费 | 100篇 |
专业分类
化学 | 5篇 |
力学 | 18篇 |
综合类 | 10篇 |
数学 | 1607篇 |
物理学 | 27篇 |
出版年
2024年 | 2篇 |
2023年 | 29篇 |
2022年 | 7篇 |
2021年 | 30篇 |
2020年 | 37篇 |
2019年 | 67篇 |
2018年 | 58篇 |
2017年 | 45篇 |
2016年 | 55篇 |
2015年 | 37篇 |
2014年 | 78篇 |
2013年 | 133篇 |
2012年 | 35篇 |
2011年 | 73篇 |
2010年 | 52篇 |
2009年 | 86篇 |
2008年 | 125篇 |
2007年 | 83篇 |
2006年 | 102篇 |
2005年 | 71篇 |
2004年 | 70篇 |
2003年 | 68篇 |
2002年 | 62篇 |
2001年 | 44篇 |
2000年 | 53篇 |
1999年 | 46篇 |
1998年 | 28篇 |
1997年 | 26篇 |
1996年 | 17篇 |
1995年 | 10篇 |
1994年 | 6篇 |
1993年 | 4篇 |
1992年 | 9篇 |
1991年 | 2篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 3篇 |
1984年 | 1篇 |
1983年 | 2篇 |
1982年 | 2篇 |
1981年 | 1篇 |
1980年 | 2篇 |
排序方式: 共有1667条查询结果,搜索用时 15 毫秒
1.
We describe a unified approach for studying book, point-set, and simultaneous embeddability problems of upward planar digraphs. The approach is based on a linear time strategy to compute an upward planar drawing of an upward planar digraph such that all vertices are collinear. Besides having impact in relevant application domains of graph drawing and computational geometry, the presented results open new research directions in the area of upward planarity with constraints of the positions of the vertices. 相似文献
2.
We consider some Sobolev-type spaces and obtain a necessary and sufficient condition for their embedding in a Lebesgue space. 相似文献
3.
该文讨论一类带有奇异系数的双重调和方程{△^2u-μu/|x|^s=f(x,u),x∈Ω,u=δu/δv=0,x∈δΩ,这里Ω包含R^N是包含0的有界光滑区域,u∈H0^2(Ω),μ∈R是参数,0≤s≤2,△^2=△△表示双重拉普拉斯算子,当f(x,u)=u^p,p=2N/N-4时,上述问题就是一个临界双重调和问题,该文运用Sobolev-Hardy不等式和变分方法,得到它的解的存在性的一些结果。 相似文献
4.
SUN Qiyu 《数学年刊B辑(英文版)》2003,24(3):367-386
In this paper, the author at first develops a method to study convergence of the cascade algorithm in a Banach space without stable assumption on the initial (see Theorem 2.1), and then applies the previous result on the convergence to characterizing compactly supported refinable distributions in fractional Sobolev spaces and Holder continuous spaces (see Theorems 3.1, 3.3, and 3.4). Finally the author applies the above characterization to choosing appropriate initial to guarantee the convergence of the cascade algorithm (see Theorem 4.2). 相似文献
5.
Karl Gustafson 《Numerical Linear Algebra with Applications》2004,11(7):649-659
Given the operator product BA in which both A and B are symmetric positive‐definite operators, for which symmetric positive‐definite operators C is BA symmetric positive‐definite in the C inner product 〈x, y〉C? This question arises naturally in preconditioned iterative solution methods, and will be answered completely here. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
6.
The concept and application of phase-space reconstructions are reviewed. Fractional derivatives are then proposed for the purpose of reconstructing dynamics from a single observed time history. A procedure is presented in which the fractional derivatives of time series data are obtained in the frequency domain. The method is applied to the Lorenz system. The ability of the method to unfold the data is assessed by the method of global false nearest neighbors. The reconstructed data is used to compute recurrences and correlation dimensions. The reconstruction is compared to the commonly used method of delays in order to assess the choice of reconstruction parameters, and also the quality of results. 相似文献
7.
8.
We prove equivalence of the definitions by the author and by Korevaar and Schoen of the Sobolev classes of mappings of a domain of an arithmetic n-dimensional space to a metric space. 相似文献
9.
Young Ja Park 《Proceedings of the American Mathematical Society》2004,132(7):2075-2083
A logarithmic Sobolev trace inequality is derived. Bounds on the best constant for this inequality from above and below are investigated using the sharp Sobolev inequality and the sharp logarithmic Sobolev inequality.
10.
This is a write-up on the foundation of the Sobolev Institute of Mathematics in 1957. 相似文献