全文获取类型
收费全文 | 155篇 |
免费 | 16篇 |
国内免费 | 16篇 |
专业分类
化学 | 66篇 |
晶体学 | 1篇 |
力学 | 2篇 |
综合类 | 6篇 |
数学 | 94篇 |
物理学 | 18篇 |
出版年
2023年 | 1篇 |
2022年 | 1篇 |
2021年 | 2篇 |
2020年 | 5篇 |
2019年 | 1篇 |
2018年 | 5篇 |
2017年 | 7篇 |
2016年 | 2篇 |
2015年 | 3篇 |
2014年 | 8篇 |
2013年 | 34篇 |
2012年 | 14篇 |
2011年 | 20篇 |
2010年 | 12篇 |
2009年 | 9篇 |
2008年 | 10篇 |
2007年 | 5篇 |
2006年 | 14篇 |
2005年 | 7篇 |
2004年 | 5篇 |
2003年 | 6篇 |
2002年 | 4篇 |
2001年 | 1篇 |
1998年 | 3篇 |
1995年 | 3篇 |
1990年 | 1篇 |
1984年 | 2篇 |
1982年 | 1篇 |
1959年 | 1篇 |
排序方式: 共有187条查询结果,搜索用时 31 毫秒
181.
Jun-Hua Dong 《Journal of fluorine chemistry》2006,127(2):205-212
The oxidation of p-methylanisole 3a, dialkoxybenzenes 3b, 3c and alkyl dialkoxybenzenes 3d-h by perfluorodi[1-(2-fluorosulfonyl) ethoxy]propionyl peroxide 1 afforded main products 4-ω-fluorosulfonylperfluoroalkyl-4-alkoxy-2,5-cyclohexa-dienones and minor ring ω-fluorosulfonylperfluoroalkylation products. The electron transfer mechanism of the reactions is also proved by ESR detection of the radical cations of the donor molecules. 相似文献
182.
A biclique B of a simple graph G is the edge-set of a complete bipartite subgraph of G. A biclique cover of G is a collection of bicliques covering the edge-set of G. Given a graph G, we will study the following problem: find the minimum number of bicliques which cover the edge-set of G. This problem will be called the minimum biclique cover problem (MBC). First, we will define the families of independent and dependent sets of the edge-set E(G) of G: F⊆E(G) will be called independent if there exists a biclique B⊆E(G) such that F⊆B, and will be called dependent otherwise. From our study of minimal dependent sets we will derive a 0-1 linear programming formulation of the following problem: find the maximum weighted biclique in a graph. This formulation may have an exponential number of constraints with respect to the number of nodes of G but we will prove that the continuous relaxation of this integer program can be solved in polynomial time. Finally we will also study continuous relaxation methods for the problem (MBC). This research was motivated by an open problem of Fishburn and Hammer. 相似文献
183.
研究了L-保序算子空间的ω-紧性.借助于Hα-ω-开覆盖,定义了L-保序算子空间的ω-紧性,证明了ω-紧集和ω-闭集之交是ω-紧的,ω-紧性被连续的广义Zadeh型函数所保持,ω-紧性是L-好的推广,Tychonoff乘积定理成立.此外,给出了ω-紧性的网式刻画. 相似文献
184.
Zdeněk Ko?an Veronika Kurková Michal Málek 《Communications in Nonlinear Science & Numerical Simulation》2012,17(8):3169-3176
For interval maps and also for graph maps, every ω-limit set is a subset of a maximal one. In this note we construct a continuous map on a dendrite with no maximal ω-limit set. Moreover, the set of branch points is nowhere dense, every ω-limit set of the map is nowhere dense, the set of periodic points and the set of recurrent points are equal and the set of ω-limit points is not closed (an example with the last property was constructed by the authors already in [Ko?an Z, Kornecká-Kurková V, Málek M. On the centre and the set of omega-limit points of continuous maps on dendrites. Topol Appl 2009;156:2923-2931]). 相似文献
185.
186.
In the note,we establish for a bounded linear operator defined on a Hilbert space the necessary and sufficient conditions for the stability of property(ω) by means of the variant of the essential approximate point spectrum and the induced spectrum of consistency in Fredholm and index.In addition,the stability of property(ω) for H(P) operators is considered. 相似文献
187.