全文获取类型
收费全文 | 112篇 |
免费 | 8篇 |
国内免费 | 1篇 |
专业分类
化学 | 75篇 |
晶体学 | 4篇 |
力学 | 9篇 |
数学 | 21篇 |
物理学 | 12篇 |
出版年
2023年 | 1篇 |
2022年 | 2篇 |
2020年 | 1篇 |
2019年 | 3篇 |
2018年 | 5篇 |
2017年 | 2篇 |
2016年 | 7篇 |
2015年 | 5篇 |
2014年 | 7篇 |
2013年 | 7篇 |
2012年 | 10篇 |
2011年 | 13篇 |
2010年 | 8篇 |
2009年 | 6篇 |
2008年 | 4篇 |
2007年 | 3篇 |
2006年 | 2篇 |
2005年 | 4篇 |
2004年 | 6篇 |
2003年 | 5篇 |
2002年 | 3篇 |
2001年 | 2篇 |
2000年 | 2篇 |
1999年 | 1篇 |
1997年 | 3篇 |
1996年 | 1篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1985年 | 1篇 |
1982年 | 1篇 |
1979年 | 2篇 |
排序方式: 共有121条查询结果,搜索用时 15 毫秒
91.
92.
93.
94.
Cafer Caliskan 《组合设计杂志》2016,24(8):343-351
Let G be a graph of order n satisfying that there exists for which every graph of order n and size t is contained in exactly λ distinct subgraphs of the complete graph isomorphic to G. Then G is called t‐edge‐balanced and λ the index of G. In this article, new examples of 2‐edge‐balanced graphs are constructed from bipartite graphs and some further methods are introduced to obtain more from old. 相似文献
95.
Microcrystalline cellulose (avicel) is treated in hot-compressed aprotic solvents,sulfolane and 1,4-dioxane,using a batch-type reaction system with a molten tin bath in a range from 290 to 390℃. The corresponding densities of the solvent are 0.25-1.26 g/cm3 and 0.21-1.03 g/cm3 for sulfolane and 1,4-dioxane,respectively. As a result,in both solvents,more than 90% of cellulose is found to be de-composed to the solvent-soluble portion in which levoglucosan is the main component with the high-est yield of about 35% on original cellulose basis. The decomposition rate to levoglucosan is,however,faster in sulfolane than in 1,4-dioxane,while levoglucosan is more stable in 1,4-dioxane. In addition,its yield is found to be solvent-density dependent to be highest around 0.4-0.5 g/cm3 for both solvents. To elucidate these decomposition behaviors,the results obtained in this study with aprotic solvents are compared with protic solvents such as water and methanol in previous works. 相似文献
96.
Continuing [6], [8] and [16], we study the consequences of the weak Freese-Nation property of (?(ω),⊆). Under this assumption,
we prove that most of the known cardinal invariants including all of those appearing in Cichoń's diagram take the same value
as in the corresponding Cohen model. Using this principle we could also strengthen two results of W. Just about cardinal sequences
of superatomic Boolean algebras in a Cohen model. These results show that the weak Freese-Nation property of (?(ω),⊆) captures
many of the features of Cohen models and hence may be considered as a principle axiomatizing a good portion of the combinatorics
available in Cohen models.
Received: 7 June 1999 / Revised version: 17 October 1999 /?Published online: 15 June 2001 相似文献
97.
Cellulose acetate being important in the fiber and textile industries is usually prepared from high quality cellulose such as cotton linters and wood pulps with an alpha cellulose content of more than 95%. In this section, therefore, wood pulps and cotton linters appropriate for cellulose acetate production were discussed in their chemical and physical properties so as to use them judiciously as natural raw materials for cellulose acetate production. 相似文献
98.
Temperature is one of the physical quantifies through which quantitative evaluation of the safety and reliability of industrial products can be achieved, and this has been used widely in practice. Under any environmental condifion, regardless of the size of the object to be inspected, accurate and reliable measurement of temperature is of great practical importance. This review article presents a simple and direct method of temperature measurement, that can be applied to the local areas with difficulty in measuring the temperature by using normal thermometers. In the present article, two different application examples are demonstrated. One addresses the study of the electromigration of solders which are used as bonding metals in electronic devices (micro-structures). The application of the method to the shaft of a motor used in heavy industrial fields is explained as the second. 相似文献
99.
Shiro Saka 《Macromolecular Symposia》2004,208(1):7-28
The molecular arrangement of wood cell wall is described in relation to the physical and mechanical properties of wood. The chemical composition of wood is also summarized to illustrate the heterogeneity in distribution of cell wall constituents to use wood plup fibers judiciously as natural raw materials for cellulose acetate production. 相似文献
100.
Co(II) and Fe(II) phthalocyanines: synthesis,investigation of their catalytic activity towards phenolic compounds and electrochemical behaviour
下载免费PDF全文
![点击此处可从《应用有机金属化学》网站下载免费的PDF全文](/ch/ext_images/free.gif)
4‐[(1‐Benzylpiperidin‐4‐yl)oxy]‐substituted cobalt(II) and iron(II) phthalocyanine complexes were synthesized and their catalytic activity towards various phenolic compounds was investigated. Converting from environmentally harmful phenolic compounds into less harmful oxidation products using phthalocyanines makes this study attractive. This catalysis is feasible and time‐saving in terms of procedure and the best oxidation conditions determined. Electrochemical studies were also carried out using cyclic voltammetry and square wave voltammetry techniques. Voltammetric analyses of the synthesized phthalocyanine complexes supported their proposed structures. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献