全文获取类型
收费全文 | 151篇 |
免费 | 6篇 |
专业分类
化学 | 149篇 |
数学 | 4篇 |
物理学 | 4篇 |
出版年
2020年 | 3篇 |
2019年 | 2篇 |
2017年 | 2篇 |
2016年 | 5篇 |
2015年 | 3篇 |
2014年 | 3篇 |
2013年 | 3篇 |
2012年 | 4篇 |
2011年 | 12篇 |
2010年 | 3篇 |
2009年 | 3篇 |
2008年 | 7篇 |
2007年 | 12篇 |
2006年 | 10篇 |
2005年 | 13篇 |
2004年 | 20篇 |
2003年 | 9篇 |
2002年 | 7篇 |
2001年 | 9篇 |
2000年 | 5篇 |
1998年 | 2篇 |
1997年 | 2篇 |
1996年 | 1篇 |
1995年 | 3篇 |
1994年 | 2篇 |
1993年 | 3篇 |
1991年 | 3篇 |
1988年 | 1篇 |
1987年 | 2篇 |
1982年 | 2篇 |
1978年 | 1篇 |
排序方式: 共有157条查询结果,搜索用时 31 毫秒
41.
Dumur F Gautier N Gallego-Planas N Sahin Y Levillain E Mercier N Hudhomme P Masino M Girlando A Lloveras V Vidal-Gancedo J Veciana J Rovira C 《The Journal of organic chemistry》2004,69(6):2164-2177
Novel fused donor-acceptor dyad (TTF-Q or D-A) and acceptor-donor-acceptor triad (Q-TTF-Q or A-D-A) incorporating the donor tetrathiafulvalene (TTF) and the acceptor p-benzoquinone (Q) have been synthesized. The solution UV-vis spectra of these molecules display a low-energy absorption band that is attributed to an intramolecular charge transfer between both antagonistic units. The presence of reversible oxidation and reduction waves for the donor and acceptor moieties was shown by cyclic voltammetry, in agreement with the ratio TTF/quinone(s) units. The successive generation from these compounds of the cation radical and anion radical obtained upon (electro)chemical oxidation and reduction, respectively, was monitored by optical and ESR spectroscopies. The anion radical Q-TTF-Q(-.) triad was demonstrated to be a class II mixed-valence system with the existence of a temperature-dependent intramolecular electron transfer. The crystallographic tendency of these fused systems to overlap in mixed stacks of alternating A-D-A units is also discussed. 相似文献
42.
43.
44.
Roques N Maspoch D Domingo N Ruiz-Molina D Wurst K Tejada J Rovira C Veciana J 《Chemical communications (Cambridge, England)》2005,(38):4801-4803
The synthesis, self assembly and magnetic properties of a polychlorotriphenylmethyl radical, substituted with six meta-carboxylic groups, are reported showing that radical-radical hydrogen bonds in the solid state yield to very weak intermolecular ferromagnetic interactions. 相似文献
45.
Laukhina E Vidal-Gancedo J Laukhin V Veciana J Chuev I Tkacheva V Wurst K Rovira C 《Journal of the American Chemical Society》2003,125(13):3948-3953
The low dimensional organic conductor (BEDT-TTF)(2)Br(1.3)I(1.1)Cl(0.6) [BEDT-TTF = bis(ethylenedithio)tertathiafulvalene] is shown to be a unique molecular solid that exists in three crystalline polymorphic forms (alpha'-, alpha' "-, beta' '-phase) and, surprisingly, is able to adopt the same metal-like beta' '-phase at both low (T < 185 K) and high (T > 395 K) temperatures. Several crystals of the alpha'- and alpha' "-phases have been studied using three different techniques: dc-conductivity measurements, ESR spectroscopy, and X-ray diffraction analysis. All these techniques show the existence of the reversible semiconductor <--> metal (alpha' " <--> beta' ') phase transition at both high and low temperatures as well as the alpha' <--> alpha' " phase transition at high temperatures. The phase transitions of these polymorphs are characterized by huge hysteresis and dramatic changes in the transport and magnetic properties. Based on ab initio calculations, it is suggested that dipole-dipole interactions can play a key role in the rich polymorphism of this molecular solid. 相似文献
46.
47.
Maspoch D Domingo N Ruiz-Molina D Wurst K Tejada J Rovira C Veciana J 《Journal of the American Chemical Society》2004,126(3):730-731
A new pure organic paramagnetic porous molecular material, which combines hydrophilic windows with large hydrophobic nanocontainers, is shown to be stable even in absence of solvent guest molecules. 相似文献
48.
49.
50.