全文获取类型
收费全文 | 106篇 |
免费 | 2篇 |
专业分类
化学 | 68篇 |
力学 | 1篇 |
物理学 | 39篇 |
出版年
2021年 | 2篇 |
2019年 | 1篇 |
2017年 | 1篇 |
2015年 | 1篇 |
2014年 | 1篇 |
2013年 | 7篇 |
2012年 | 2篇 |
2011年 | 9篇 |
2010年 | 4篇 |
2008年 | 7篇 |
2007年 | 10篇 |
2006年 | 11篇 |
2005年 | 7篇 |
2004年 | 3篇 |
2003年 | 3篇 |
2002年 | 8篇 |
2001年 | 3篇 |
2000年 | 4篇 |
1999年 | 1篇 |
1996年 | 1篇 |
1995年 | 4篇 |
1994年 | 3篇 |
1991年 | 2篇 |
1990年 | 2篇 |
1988年 | 5篇 |
1987年 | 2篇 |
1986年 | 2篇 |
1985年 | 1篇 |
1982年 | 1篇 |
排序方式: 共有108条查询结果,搜索用时 15 毫秒
101.
Reaction intermediates in the photoreduction of oxygen molecules at the (101) TiO2 (anatase) surface
Mattioli G Filippone F Amore Bonapasta A 《Journal of the American Chemical Society》2006,128(42):13772-13780
The structural, electronic, and vibrational properties of intermediates of the O(2) photoreduction at the (101) TiO(2) (anatase) surface have been investigated by performing ab initio density functional calculations. In detail, a recently proposed approach has been used where molecules on the surface are treated like surface defects. Thus, by applying theoretical methods generally used in the physics of semiconductors, we successfully estimate the location and donor/acceptor character of the electronic levels induced by an adsorbed molecule in the TiO(2) energy gap, both crucial for the surface-molecule charge-transfer processes, and investigate the formation and the properties of charged intermediates. The present approach permits a view of the O(2) photoreduction process through several facets, which elucidates the molecule-surface charge-transfer conditions and reveals the key role played by charged intermediates. A comparison of present results with those of a highly sensitive IR (infrared) spectroscopy study of intermediates of the O(2) photoreduction leads to a deeper understanding of this process and to revised vibrational-line assignments and reaction paths. 相似文献
102.
Bonapasta AA Filippone F Giannozzi P Capizzi M Polimeni A 《Physical review letters》2002,89(21):216401
In GaAsyN(1-y), the presence of a few percent of N induces a large reduction of the GaAs band gap that vanishes upon hydrogenation. In the present Letter, the energetics of N-H complexes and their effects on the band structure of the GaAs0.97N0.03 alloy have been investigated by first-principles density functional methods. We find that monohydrogen N-H+ and dihydrogen N-H* 2 complexes are formed depending on doping. Moreover, only N-H* 2 complexes account for the neutralization of nitrogen effects. A model is proposed that clarifies the passivation mechanism of nitrogen by H. 相似文献
103.
104.
van der Pol C Bryce MR Wielopolski M Atienza-Castellanos C Guldi DM Filippone S Martín N 《The Journal of organic chemistry》2007,72(18):6662-6671
Two complementary series of C(60)-(Fl)(n) and C(60)-(Fl)(n)-C60 (Fl = 9,9-dihexylfluorene-2,7-diyl; n = 1-5) derivatives with terminal N-methylfulleropyrrolidine units have been synthesized from CHO-(Fl)(n) and CHO-(Fl)(n)-CHO precursors via 1,3-dipolar cycloaddition reaction of in situ generated azomethine ylides with an excess of C60. In solution electrochemical experiments, these conjugates give rise to amphoteric redox behavior. Three consecutive quasireversible reduction waves have been observed at the expected potentials for the N-methylfulleropyrrolidine cores. For the C(60)-(Fl)(n)-C(60) series, each reduction wave is a two-electron process with no observable interaction between the C(60) units. Two or, in some cases, three oxidation waves--most of them irreversible--are ascribed to the oligofluorene system. These waves are cathodically shifted with an increasing number of fluorene units and anodically shifted by the conjugated terminal aldehyde units, compared to the N-methylfulleropyrrolidine termini. Steady-state and time-resolved photolytic techniques show that an efficient transduction of singlet excited-state energy transfer prevails from the photoexcited oligofluorene to the energy accepting fullerene. 相似文献
105.
Delgado JL Filippone S Martín-Domenech A Altable M Maroto E Langa F Martín N Martínez-Alvarez R 《Journal of the American Society for Mass Spectrometry》2011,22(3):557-567
Substituted pyrrolidino- and 3-alkyl-2-pyrazolinofullerenes ionize under ESI and MALDI mass spectrometry conditions and negative
mode of detection undergoing mass spectral fragmentations, which can be easily correlated with the reported results for the
thermal and electrochemical retro-cycloaddition reactions of these compounds. 2-Pyrazolinofullerenes lead directly to a [60]fullerene
product ion formed through a retro-cycloaddition process regardless of the substituents attached at the carbon and nitrogen
atoms of the heterocyclic ring. These results are different from whose reported for the thermal and electrochemical processes.
In contrast, pyrrolidinofullerenes undergo different fragmentative reactions depending upon the substituents (hydrogen, alkyl,
or acyl) attached at the nitrogen atom of the heterocyclic ring leading eventually to the pristine C60 in the last step of the fragmentation pathway. 相似文献
106.
107.