全文获取类型
收费全文 | 276篇 |
免费 | 5篇 |
国内免费 | 4篇 |
专业分类
化学 | 91篇 |
力学 | 13篇 |
数学 | 112篇 |
物理学 | 69篇 |
出版年
2023年 | 1篇 |
2022年 | 7篇 |
2021年 | 7篇 |
2020年 | 4篇 |
2018年 | 3篇 |
2017年 | 4篇 |
2016年 | 2篇 |
2015年 | 9篇 |
2014年 | 4篇 |
2013年 | 140篇 |
2012年 | 2篇 |
2011年 | 9篇 |
2010年 | 2篇 |
2009年 | 8篇 |
2008年 | 9篇 |
2007年 | 6篇 |
2006年 | 12篇 |
2005年 | 12篇 |
2004年 | 9篇 |
2003年 | 6篇 |
2002年 | 10篇 |
2001年 | 2篇 |
2000年 | 5篇 |
1999年 | 1篇 |
1998年 | 1篇 |
1994年 | 3篇 |
1993年 | 4篇 |
1987年 | 1篇 |
1984年 | 1篇 |
1897年 | 1篇 |
排序方式: 共有285条查询结果,搜索用时 15 毫秒
121.
122.
123.
124.
George L. Karakostas S. Stević † 《Journal of Difference Equations and Applications》2013,19(9):809-815
The boundedness, global attractivity, oscillatory and asymptotic periodicity of the nonnegative solutions of the difference equation?in the title is investigated, where all the coefficients are nonnegative real numbers. The paper is motivated by an open problem proposed by Ladas [Open problems and conjectures, J. Differ. Equations?Appl., 5 (1999), 211–215]. 相似文献
125.
Using reparametrizations of linear flows, we show that thereexist area-preserving real analytic maps of the three-dimensionaltorus that are mixing of all orders and do notenjoy the monotone shrinking target property. Prior to that,we give a short proof of a result of Kurzweil from 1955: namely,that a translation T of the torus Td has the monotone shrinkingtarget property if and only if the vector is badly approximable(that is, of constant type). 2000 Mathematics Subject Classification37E45, 37A25, 11J13. 2000 Mathematics Subject Classification37E45, 37A25, 11J13. 相似文献
126.
127.
Bassam Mourad 《Linear and Multilinear Algebra》2004,52(2):99-113
In this article, we study generalized doubly stochastic matrices using the theory of Lie groups and Lie algebras. Applications to the inverse eigenvalue problem for symmetric doubly stochastic matrices are presented. 相似文献
128.
Bassam R. Fayad 《Bulletin of the Brazilian Mathematical Society》2000,31(3):277-285
We give an example of an analytic transformation onT
5 that conserves the Haar measure, that is minimal and topologically mixing, but is not ergodic. 相似文献
129.
Synthesis of tin oxides SnO2–x in the entire composition range (x = 0 to 1) by ion‐beam sputter‐deposition
下载免费PDF全文
![点击此处可从《固体物理学:研究快报》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Ion‐beam sputter‐deposition (IBSD) was used to reactively deposit tin oxide crystalline films at oxygen fluxes of 3–15 sccm and at substrate temperatures of 100–600 °C. Analysing the samples by X‐ray diffraction and Raman spectro‐ scopy yields a map of the crystalline structures in dependence on the growth parameters. In addition to SnO2, pure SnO films of high quality and an intermediate phase such as Sn2O3 or Sn3O4 can be reproducibly obtained. Thus, IBSD is, to our knowledge, the only thin‐film deposition technique verified yet to reliably produce samples in the entire composition range of tin oxides. (© 2015 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim) 相似文献
130.
Ana M. Costero Joaquín Sanchis Salvador Gil Vicente Sanz M. Carmen Ramírez De Arellano J.A. Gareth Williams † 《Supramolecular chemistry》2013,25(6):435-446
Eight new polyazapodands containing a 4,4′-substituted biphenyl moiety have been synthesised. Four (7, 8, 9 and 11) are functionalised on positions 4 and 4′ with a nitro group and four (1, 2, 3 and 10) with a dimethylamino substituent. Comparison of the emission behaviour of 1, 2, 3 with that of the reference compounds 10 and tetramthylbenzidine, clearly suggests that a modification in the dihedral angle between the biphenyl rings is an important factor in determining the fluorescent response of the molecule. The fluorescence is pH dependent, due to the formation of intramolecular hydrogen bonds between protonated aliphatic nitrogens and a carbonyl oxygen, which influences the aforementioned dihedral angle. A crystal structure resolved by X-ray diffraction of 7·2HCl has been determined, and confirms the dependence of the angle and the rigidity on the hydrogen bonding. The complexation properties of these ligands have been studied with Zn2+, Cd2+, Ni2+, Cu2+ and Pb2+, which show that the number of amino groups within the pendants has a strong influence on the nature of the complexation and the fluorescent response of each ligand. 相似文献