全文获取类型
收费全文 | 114篇 |
免费 | 5篇 |
国内免费 | 1篇 |
专业分类
化学 | 6篇 |
综合类 | 1篇 |
数学 | 112篇 |
物理学 | 1篇 |
出版年
2024年 | 1篇 |
2023年 | 2篇 |
2022年 | 4篇 |
2021年 | 3篇 |
2020年 | 5篇 |
2019年 | 8篇 |
2018年 | 6篇 |
2017年 | 1篇 |
2016年 | 1篇 |
2015年 | 3篇 |
2014年 | 3篇 |
2013年 | 6篇 |
2012年 | 1篇 |
2011年 | 10篇 |
2010年 | 9篇 |
2009年 | 13篇 |
2008年 | 7篇 |
2007年 | 5篇 |
2006年 | 1篇 |
2005年 | 4篇 |
2004年 | 4篇 |
2003年 | 3篇 |
2002年 | 5篇 |
2001年 | 2篇 |
1999年 | 2篇 |
1998年 | 4篇 |
1997年 | 4篇 |
1995年 | 1篇 |
1990年 | 1篇 |
1984年 | 1篇 |
排序方式: 共有120条查询结果,搜索用时 31 毫秒
1.
2.
胺、醇、醚类化合物电离能的自相关拓扑研究 总被引:1,自引:3,他引:1
原子的染色序数 fi 定义为 :fi=gi·xi,式中 gi 为原子i在分子中的序数 ,xi 为其染色系数 .基于fi 建立改进的原子序数自相关拓扑指数mF ,其中的1F对烷烃及其衍生物具有良好的结构选择性 .使用第一电离能 (Ip)与0 F ,1F的数量关系模型对 32种脂肪族胺、醇、醚进行估算、预测 ,结果令人满意 相似文献
3.
Monochrome coloured glass beads of the Merovingians (5th–7th cent. AD) have been examined by different analytical methods. The elemental composition of a large number of mostly unprepared
beads have been measured non-destructively by X-ray fluorescence analysis. After subtracting the content of the colouring
oxides of the glass beads and normalising the residual values to 100% an identical soda-lime-glass matrix was obtained. X-ray
diffraction was used for the identification of the crystalline colouring and opacifying pigments (SnO2, Cu, Cu2O, PbSnO3), and scanning electron microscopy as well as electron probe microanalysis were applied to study the microstructure and the
composition of white, brown, green, orange and yellow coloured glass beads. Oxidised metals, alloys (lead, copper, bronze,
brass and mixtures of them) and iron smelting slag have been identified as raw materials to colour the soda-lime-glass. 相似文献
4.
Marién Abreu Jan Goedgebeur Domenico Labbate Giuseppe Mazzuoccolo 《Journal of Graph Theory》2019,92(4):415-444
A -bisection of a bridgeless cubic graph is a -colouring of its vertex set such that the colour classes have the same cardinality and all connected components in the two subgraphs induced by the colour classes ( monochromatic components in what follows) have order at most . Ban and Linial Conjectured that every bridgeless cubic graph admits a -bisection except for the Petersen graph. A similar problem for the edge set of cubic graphs has been studied: Wormald conjectured that every cubic graph with has a -edge colouring such that the two monochromatic subgraphs are isomorphic linear forests (ie, a forest whose components are paths). Finally, Ando conjectured that every cubic graph admits a bisection such that the two induced monochromatic subgraphs are isomorphic. In this paper, we provide evidence of a strong relation of the conjectures of Ban-Linial and Wormald with Ando's Conjecture. Furthermore, we also give computational and theoretical evidence in their support. As a result, we pose some open problems stronger than the above-mentioned conjectures. Moreover, we prove Ban-Linial's Conjecture for cubic-cycle permutation graphs. As a by-product of studying -edge colourings of cubic graphs having linear forests as monochromatic components, we also give a negative answer to a problem posed by Jackson and Wormald about certain decompositions of cubic graphs into linear forests. 相似文献
5.
6.
Jakub Przybyło 《Random Structures and Algorithms》2015,47(4):776-791
Consider a simple graph G = (V,E) and its proper edge colouring c with the elements of the set {1,2,…,k}. The colouring c is said to be neighbour sum distinguishing if for every pair of vertices u, v adjacent in G, the sum of colours of the edges incident with u is distinct from the corresponding sum for v. The smallest integer k for which such colouring exists is known as the neighbour sum distinguishing index of a graph and denoted by . The definition of this parameter, which makes sense for graphs containing no isolated edges, immediately implies that , where Δ is the maximum degree of G. On the other hand, it was conjectured by Flandrin et al. that for all those graphs, except for C5. We prove this bound to be asymptotically correct by showing that . The main idea of our argument relays on a random assignment of the colours, where the choice for every edge is biased by so called attractors, randomly assigned to the vertices. © 2014 Wiley Periodicals, Inc. Random Struct. Alg., 47, 776–791, 2015 相似文献
7.
Kathryn A. Dowsland 《Discrete Applied Mathematics》2008,156(3):313-324
The focus of this paper is an ant colony optimisation heuristic for the graph colouring problem. We start by showing how a series of improvements enhance the performance of an existing ant colony approach to the problem and then go on to demonstrate that a further strengthening of the construction phase, combined with a tabu search improvement phase, raise the performance to the point where it is able to compete with some of the best-known approaches on a series of benchmark problems. 相似文献
8.
We prove that the list chromatic index of a graph of maximum degree Δ and treewidth is Δ; and that the total chromatic number of a graph of maximum degree Δ and treewidth is . This improves results by Meeks and Scott. 相似文献
9.
By establishing the connection between graph colouring and the solution of some equation systems in finite fields, we obtain some formulas to the number of solutions of some equation systems in finite fields, in terms of chromatic polynomial of a graph. 相似文献
10.
Stefanie Gerke 《Discrete Mathematics》2007,307(13):1668-1671
The r-acyclic edge chromatic number of a graph G is the minimum number of colours required to colour the edges of G in such a way that adjacent edges receive different colours and every cycle C receives at least min{|C|,r} colours. We prove that for any integer r?4, the r-acyclic edge chromatic number of any graph G with maximum degree Δ and with girth at least 3(r-1)Δ is at most 6(r-1)Δ. 相似文献