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   190篇
  免费   11篇
  国内免费   7篇
化学   139篇
晶体学   1篇
力学   3篇
数学   38篇
物理学   27篇
  2023年   3篇
  2022年   7篇
  2021年   11篇
  2020年   4篇
  2019年   17篇
  2018年   20篇
  2017年   7篇
  2016年   10篇
  2015年   9篇
  2014年   8篇
  2013年   31篇
  2012年   9篇
  2011年   16篇
  2010年   11篇
  2009年   8篇
  2008年   7篇
  2007年   5篇
  2006年   5篇
  2005年   3篇
  2004年   2篇
  2003年   2篇
  2002年   2篇
  2000年   1篇
  1998年   1篇
  1997年   2篇
  1996年   1篇
  1995年   2篇
  1992年   1篇
  1987年   1篇
  1984年   2篇
排序方式: 共有208条查询结果,搜索用时 46 毫秒
1.
It has come to our attention that this article, “Rheology, Morphology, and Estimation of the Interfacial Tension of Binary Blends Based on Low‐Density Polyethylene/Poly(trimethylene terephthalate) and High‐Density Polyethylene/Poly(trimethylene terephthalate)” by A. A. Shokri and S. E. Zamani was previously published under the title, “Rheology, Morphology and Estimation of Interfacial Tension of LDPE/EVA and HDPE/EVA Blends” by H. A. Khonakdar, S. H. Jafari, A. Yavari, A. Asadinezhad, U. Wagenknecht, in Polymer Bulletin 54, 75–84 (2005), . We have retracted the article, and offer our apologies to the authors of the original paper.  相似文献   
2.
Some new N‐glycosides of 4‐(2‐phenylethyl)‐5‐pyridyl‐1,2,4‐triazole‐3‐thiones were synthesised by the coupling reaction of halo sugar with 4,5‐disubstituted 3H‐1,2,4‐triazole‐3‐thiones in the presence of mercuric cyanide and dry nitromethane as solvent, followed by deprotection using dry ammonia in methanol. All of the above compounds were fully characterized by means of infrared, 1H NMR spectroscopy, mass spectroscopy and elemental analysis.  相似文献   
3.
A variety of alcoholic TBDMS (t-butyldimethylsilyl) ethers are easily removed in excellent yields by treatment with a catalytic amount of N-iodosuccinimide (NIS, 5 mol %) in methanol. This method is able to deprotect TBDMS ethers of alcohols in the presence of TBDMS ethers of phenols.  相似文献   
4.
A series of novel TIQ based N,N′-oxide ligands were synthesised and screened for their catalytic activity in the enantioselective conjugate addition of thioglycolate to chalcones. Bulky groups on the side chain of the TIQ backbone provided the highest enantioselectivity of up to 88% with 10 mol % catalyst loading. It was also observed that these reactions proceeded optimally in the presence of dichloromethane as a solvent. Screening of various metals emphasized La(OTf)3 as the ideal pre-catalyst for this particular reaction.  相似文献   
5.
An environmentally benign aqueous protocol for the synthesis of 3,4-dihydropyrimidin-2-(1H)-ones and thiones promoted by a green catalyst,silica gel-supported L-pyrrolidine-2-carboxylic acid-4-hydrogen sulfate,has been developed.The use of nontoxic,thermally stable and inexpensive amino acid catalyst makes the process simple with minimal amount of chemical waste.Compared with classical Biginelli reaction conditions,this new method has the advantages of high yields and simple workup procedures.  相似文献   
6.
7.
Sarvarian  Susan  Zamani  Mehdi 《Structural chemistry》2021,32(3):1205-1217
Structural Chemistry - In this study, density functional theory (DFT) was employed to predict thermochemical and energetic properties for single-walled carbon nanotubes (SWCNTs) decorated with one...  相似文献   
8.
Research on Chemical Intermediates - A dual-functional silica-based catalyst was prepared by treating fumed silica with amino-containing silane then 1,4-butane sultone. The presence of functional...  相似文献   
9.
Research on Chemical Intermediates - In this study, a kind of magnetic Fe3O4@mTiO2-GO (where m was shorted mesoporous) hybrids with core–shell nano-structure for controlled dual targeted drug...  相似文献   
10.
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