全文获取类型
收费全文 | 243篇 |
免费 | 20篇 |
国内免费 | 13篇 |
专业分类
化学 | 275篇 |
物理学 | 1篇 |
出版年
2023年 | 3篇 |
2022年 | 3篇 |
2021年 | 5篇 |
2020年 | 5篇 |
2019年 | 4篇 |
2018年 | 8篇 |
2017年 | 7篇 |
2016年 | 10篇 |
2015年 | 10篇 |
2014年 | 11篇 |
2013年 | 58篇 |
2012年 | 15篇 |
2011年 | 14篇 |
2010年 | 10篇 |
2009年 | 12篇 |
2008年 | 13篇 |
2007年 | 24篇 |
2006年 | 12篇 |
2005年 | 9篇 |
2004年 | 9篇 |
2003年 | 6篇 |
2002年 | 4篇 |
2001年 | 2篇 |
2000年 | 3篇 |
1999年 | 3篇 |
1998年 | 2篇 |
1997年 | 2篇 |
1996年 | 3篇 |
1995年 | 1篇 |
1994年 | 2篇 |
1993年 | 2篇 |
1992年 | 3篇 |
1987年 | 1篇 |
排序方式: 共有276条查询结果,搜索用时 488 毫秒
1.
K. C. Kumara Swamy E. Balaraman M. Phani Pavan N. N. Bhuvan Kumar K. Praveen Kumar N. Satish Kumar 《Journal of Chemical Sciences》2006,118(6):495-501
The diversity of products in the reaction of diethyl azodicarboxylate (DEAD)/diisopropyl azodicarboxylate (DIAD) and activated
acetylenes with PIII compounds bearing oxygen or nitrogen substituents is discussed. New findings that are useful in understanding the nature
of intermediates involved in the Mitsunobu reaction are highlighted. X-ray structures of two new compounds (2-t-Bu-4-MeC6H3O)P (μ-N-t-Bu)2P+[(NH-t-Bu)N[(CO2]-i-Pr)(HNCO2-i-Pr)]](Cl-)(2-t-Bu-4-MeC6H3OH)(23)and [CH2(6-t-Bu-4-Me-C6H2O)2P(O)C(CO2Me)C-(CO2Me)CClNC(O)Cl] (33) are also reported. The structure of23 is close to one of the intermediates proposed in the Mitsunobu reaction. 相似文献
2.
T. N. Pashirova S. S. Lukashenko E. M. Kosacheva L. Z. Rizvanova G. A. Gainanova I. R. Knyazeva A. R. Burilov L. A. Kudryavtseva A. I. Konovalov 《Russian Chemical Bulletin》2007,56(5):959-966
Aggregation in poly(ethylenimine)-calix[4]resorcinarene-water-DMF systems was studied by the methods of conductometry and
dynamic light scattering. The sizes (radii) of the aggregates formed and the critical micelle concentrations were determined.
The catalytic activity for these systems in the hydrolisys of phosphorus acid esters was shown.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 924–931, May, 2007. 相似文献
3.
R. A. Shagidullina E. P. Zhil'tsova L. A. Kudryavtseva 《Russian Chemical Bulletin》1998,47(9):1686-1689
The reaction ofn-hexylamine withO-alkylO-4-nitrophenyl chloromethylphosphonates in toluene solutions of poly(ethylene glycol)-600 monolaurate (PM) has been studied
by spectrophotometry. The reverse micelles of the nonionic surfactant increase more than tenfold the observed rate constant
of aminolysis. The catalytic activity of the surfactant is practically independent of the alkyl radical length of phosphonate.
An increase in the concentration of amine results in a decrease in the catalytic efficiency. The character of the dependence
of the rate constant on the concentration of PM is affected by the alkyl chain length of the substrate.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1735–1738, September, 1998. 相似文献
4.
E. D. Matveeva T. A. Podrugina M. V. Prisyazhnoi I. N. Rusetskaya N. S. Zefirov 《Russian Chemical Bulletin》2007,56(4):798-805
Interaction of aliphatic and aromatic aldehydes and ketones with optically active L-α-amino acids or their esters in the three-component catalytic one-pot synthesis of α-aminophosphonates was studied. The
corresponding α-amino phosphonates are formed in high yields as mixtures of diastereomers.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 768–774, April, 2007. 相似文献
5.
(Z)-γ-Cyano-β-perfluoroalkyl-β,γ-unsaturated esters have been synthesized by the reaction of perfluoroacylated phosphonates with organozinc reagent in 50-71% (three steps) yields. 相似文献
6.
Summary The conformation and relative configuration of [1-(2H-azirin-2-yl)alkyl]phosphonates (2) has been established by thorough investigation of some characteristic representatives of the series by1H,13C,15N, and31P NMR spectroscopy. It is shown that the chemical shift of the proton located to the phosphonate group can be used as a criterion for the discrimination and stereochemical assignment of diastereoisomers. NMR spectroscopic features of the compounds are discussed in terms of structural relationships.Dedicated to Univ.-Prof. Dr.K. Schlögl with the best wishes to his 70th birthday 相似文献
7.
PEPAMP是应用于工业循环水中的新一代高效阻垢剂.采用电喷雾电离质谱和质谱/质谱技术分析了合成产物,注射泵直接进样,正离子方式检测,方法简便、快速.通过EI-MS技术获得了目标产物PEPAMP及主要副产物的准分子离子峰,通过ESI-MS-MS技术获得了其碎片信息,并对目标化合物及主要副产物进行了精确质量测定,确定了目标化合物及主要副产物的结构. 相似文献
8.
Bujoli B Lane SM Nonglaton G Pipelier M Léger J Talham DR Tellier C 《Chemistry (Weinheim an der Bergstrasse, Germany)》2005,11(7):1980-1988
A new process for preparing oligonucleotide arrays is described that uses surface grafting chemistry which is fundamentally different from the electrostatic adsorption and organic covalent binding methods normally employed. Solid supports are modified with a mixed organic/inorganic zirconium phosphonate monolayer film providing a stable, well-defined interface. Oligonucleotide probes terminated with phosphate are spotted directly on to the zirconated surface forming a covalent linkage. Specific binding of terminal phosphate groups with minimal binding of the internal phosphate diesters has been demonstrated. The mixed organic/inorganic thin films have also been extended for use arraying DNA duplex probes, and therefore represent a viable general approach to DNA-based bioarrays. Ideas for interfacing mixed organic/inorganic interfaces to other bioapplications are also discussed. 相似文献
9.
Xin ZhangDonald J. Burton 《Journal of fluorine chemistry》2002,116(1):15-18
The organometallic reagent, (EtO)2P(O)CF2ZnBr, reacts with 1-alkynyl halides (halide=Br, I) in the presence of Cu(I)Br to give good yields of α,α-difluoropropargylphosphonates via a one pot reaction. 相似文献
10.
Laurent Griffe Dr. Mary Poupot Dr. Patrice Marchand Dr. Alexandrine Maraval Dr. Cédric‐Olivier Turrin Dr. Olivier Rolland Pascal Métivier Dr. Gérard Bacquet Dr. Jean‐Jacques Fournié Dr. Anne‐Marie Caminade Dr. Rémy Poupot Dr. Jean‐Pierre Majoral Dr. 《Angewandte Chemie (International ed. in English)》2007,46(14):2334-2334