首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   116篇
  免费   2篇
化学   71篇
数学   31篇
物理学   16篇
  2022年   4篇
  2020年   4篇
  2019年   2篇
  2018年   1篇
  2017年   1篇
  2016年   2篇
  2015年   4篇
  2014年   1篇
  2013年   7篇
  2012年   5篇
  2011年   6篇
  2010年   11篇
  2009年   4篇
  2008年   2篇
  2007年   8篇
  2006年   6篇
  2005年   8篇
  2004年   5篇
  2003年   4篇
  2002年   9篇
  1999年   2篇
  1998年   2篇
  1997年   2篇
  1996年   5篇
  1995年   1篇
  1994年   1篇
  1993年   1篇
  1990年   1篇
  1986年   1篇
  1984年   1篇
  1982年   1篇
  1981年   1篇
  1977年   3篇
  1973年   1篇
  1938年   1篇
排序方式: 共有118条查询结果,搜索用时 0 毫秒
31.
Luteinizing hormone-releasing hormone, pGlu-His-Trp-Ser-Tyr-Gly-Leu-Arg-Pro-Gly-NH2,2 was synthesized in a stepwise manner by two approaches: the use of insoluble polymeric active esters derived from (4-hydroxy-3-nitro)benzylated polystyrene and that of solubleN,N-dicyclohexylcarbodiimide. The overall yields of the syntheses were 40 and 7%, respectively. The efficiencies of the two synthetic routes, in which identical intermediate peptides were prepared, are compared.  相似文献   
32.
We present a new, completely three-dimensional proof of the fact, due to the combined work of Gabai and Eliashberg-Thurston, that every closed, oriented, connected, irreducible 3-manifold with nonzero second homology carries a universally tight contact structure.  相似文献   
33.
Some generalizations of Ostrowski inequality for Hölder functions and functions with bounded derivatives are given.  相似文献   
34.
35.
Journal of Thermal Analysis and Calorimetry - We investigated various possible chemical interactions between individual precursor compounds (ZnSe, SnSe, and CuSe) and CdI2 as a flux material used...  相似文献   
36.
37.
It is shown that all maximal regular ideals in a Hausdorff topological algebra A are closed if the von Neumann bornology of A has a pseudo-basis which consists of idempotent and completant absolutely pseudoconvex sets. Moreover, all ideals in a unital commutative sequentially Mackey complete Hausdorff topological algebra A with jointly continuous multiplication and bounded elements are closed if the von Neumann bornology of A is idempotently pseudoconvex.  相似文献   
38.
We present a couple of general inequalities related to the Jensen-Steffensen inequality in its discrete and integral form. The Jensen-Steffensen inequality, Slater’s inequality and a generalization of the counterpart to the Jensen-Steffensen inequality are deduced as special cases from these general inequalities.  相似文献   
39.
Surface treatment of titanium (Ti) surface has been extensively studied to improve its properties for biomedical applications, including hydrophilicity, corrosion resistance, and tissue integration. In this present work, we present the effects of thermal oxidation as surface modification method on metallic titanium (Ti). The Ti foils were oxidized at 300°C, 400°C, 500°C, and 600°C under air atmosphere for 3 hours, which formed oxide layer on Ti surface. The physicochemical properties including surface chemistry, roughness, and thickness of the oxide layer were evaluated in order to investigate how these factors affected surface hydrophilicity, microhardness, and corrosion resistance properties of the Ti surface. The results revealed that surfaces of all oxidized samples were modified by formation of titanium dioxide layer, of which morphology, phase, and thickness were changed according to the oxidized temperatures. Increasing oxidation temperature led to the formation of thicker oxide layer and phase transformation of anatase to rutile. The presence of the oxide layer helped the improvement of corrosion resistance and microhardness. The most improvement in surface roughness was found in the specimens treated at 400°C, which significantly improved surface hydrophilicity. But both surface roughness and hydrophilicity reduced when oxidized at 500°C and 600°C, suggesting that hydrophilicity was dominated by the surface roughness. In addition, this surface treatment did not reduce the biocompatibility of the metallic Ti substrates against murine osteoblasts (MC3T3).  相似文献   
40.
Atomic-scale surface demixing in a eutectic liquid BiSn alloy   总被引:1,自引:0,他引:1  
Resonant x-ray reflectivity of the surface of the liquid phase of the Bi(43)Sn(57) eutectic alloy reveals atomic-scale demixing extending over three near-surface atomic layers. Because of the absence of an underlying atomic lattice which typically defines adsorption in crystalline alloys, studies of adsorption in liquid alloys provide unique insight on interatomic interactions at the surface. The observed composition modulation could be accounted for quantitatively by the Defay-Prigogine and Strohl-King multilayer extensions of the single-layer Gibbs model, revealing a near-surface domination of the attractive Bi-Sn interaction over the entropy.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号