全文获取类型
收费全文 | 183篇 |
免费 | 27篇 |
国内免费 | 3篇 |
专业分类
化学 | 183篇 |
晶体学 | 1篇 |
数学 | 8篇 |
物理学 | 21篇 |
出版年
2022年 | 2篇 |
2021年 | 3篇 |
2020年 | 7篇 |
2019年 | 7篇 |
2018年 | 7篇 |
2017年 | 1篇 |
2016年 | 15篇 |
2015年 | 14篇 |
2014年 | 8篇 |
2013年 | 11篇 |
2012年 | 15篇 |
2011年 | 18篇 |
2010年 | 3篇 |
2009年 | 3篇 |
2008年 | 12篇 |
2007年 | 18篇 |
2006年 | 14篇 |
2005年 | 7篇 |
2004年 | 9篇 |
2003年 | 6篇 |
2002年 | 10篇 |
2001年 | 3篇 |
2000年 | 3篇 |
1999年 | 2篇 |
1998年 | 3篇 |
1996年 | 3篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1983年 | 1篇 |
1980年 | 2篇 |
1979年 | 1篇 |
1976年 | 1篇 |
排序方式: 共有213条查询结果,搜索用时 15 毫秒
41.
42.
Muraoka T Kinbara K Kobayashi Y Aida T 《Journal of the American Chemical Society》2003,125(19):5612-5613
The first example of "light-driven chiral molecular scissors" (1), which consists of 1,1',3,3'-tetraarylferrocene as a pivot part and azobenzene as a driving part, was synthesized. Absorption, circular dichroism (CD), and 1H NMR spectral studies on the photoinduced isomerization process of an enantiomer of 1 agreed well with a prediction by a DFT calculation, where a motion of the handles via light-driven contraction/expansion of the connecting azobenzene strap was transformed, through a pivotal motion of the ferrocene unit, into an open-close motion of the blade parts. 相似文献
43.
Rüffer T Ohashi M Shima A Mizomoto H Kaneda Y Mashima K 《Journal of the American Chemical Society》2004,126(39):12244-12245
Reaction of Mo2(pyphos)4 (1) with [RhCl(CO)2]2 followed by treatment of excess amounts of tBuNC resulted in the clean formation of [Mo2Rh2(tBuNC)4(pyphos)4](X)2 (4a; X = Cl). The X-ray diffraction study as well as spectroscopic analyses of 4c (X = BPh4) implied that there is no direct sigma-bonding interaction between each Rh(I) atom and the Mo2 core. Each Rh(I) atom in 4 can be oxidized concurrently by 2 equiv of [Cp2Fe]PF6 to afford [Mo2Rh2(Cl)2(tBuNC)4(pyphos)4](PF6)2 (5) along with the formation of two Mo-Rh(II) single bonds and the reduction of the bond orders of the Mo-Mo moiety. 相似文献
44.
This short review describes the preparation, structure and reactivity of 1,3-diene complexes of niobium and tantalum and presents a comparison with the similar diene complexes of metals of Group 2, 3 and 4. 相似文献
45.
46.
Taguchi H Ghoroku K Tadaki M Tsubouchi A Takeda T 《The Journal of organic chemistry》2002,67(24):8450-8456
Successive treatment of the (Z)-gamma-trimethylsilyl allylic alcohols with copper(I) tert-butoxide and allylic halides followed by the tetrabutylammonium fluoride-assisted hydrolysis produced the allylation products, 2,5-alkadien-1-ols, with complete retention of configuration. Similar treatment of the organometallic intermediates with aryl and vinylic halides in the presence of palladium(0) catalyst gave the corresponding cross-coupling products in good yields. The stereoselective preparation of the starting materials is also described. 相似文献
47.
48.
Cerium‐Complex‐Catalyzed Oxidation of Arylmethanols under Atmospheric Pressure of Dioxygen and Its Mechanism through a Side‐On μ‐Peroxo Dicerium(IV) Complex 下载免费PDF全文
Mitali Paul Satoru Shirase Dr. Yuma Morimoto Dr. Laurent Mathey Dr. Balasubramanian Murugesapandian Dr. Shinji Tanaka Prof. Dr. Shinobu Itoh Prof. Dr. Hayato Tsurugi Prof. Dr. Kazushi Mashima 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(12):4008-4014
A new CeIV complex [Ce{NH(CH2CH2N=CHC6H2‐3,5‐(tBu)2‐2‐O)2}(NO3)2] ( 1 ), bearing a dianionic pentadentate ligand with an N3O2 donor set, has been prepared by treating (NH4)2Ce(NO3)6 with the sodium salt of ligand L1 . Complex 1 in the presence of TEMPO and 4 Å molecular sieves (MS4 A) has been found to serve as a catalyst for the oxidation of arylmethanols using dioxygen as an oxidant. We propose an oxidation mechanism based on the isolation and reactivity study of a trivalent cerium complex [Ce{NH(CH2CH2N=CHC6H2‐3,5‐(tBu)2‐2‐O)2}(NO3)(THF)] ( 2 ), its side‐on μ‐O2 adduct [Ce{NH(CH2CH2N=CHC6H2‐3,5‐(tBu)2‐2‐O)2}(NO3)]2(μ‐η2:η2‐O2) ( 3 ), and the hydroxo‐bridged CeIV complex [Ce{NH(CH2CH2N=CHC6H2‐3,5‐(tBu)2‐2‐O)2}(NO3)]2(μ‐OH)2 ( 4 ) as key intermediates during the catalytic cycle. Complex 2 was synthesized by reduction of 1 with 2,5‐dimethyl‐1,4‐bis(trimethylsilyl)‐1,4‐diazacyclohexadiene. Bubbling O2 into a solution of 2 resulted in formation of the peroxo complex 3 . This provides the first direct evidence for cerium‐catalyzed oxidation of alcohols under an O2 atmosphere. 相似文献
49.
50.