全文获取类型
收费全文 | 149篇 |
免费 | 4篇 |
专业分类
化学 | 105篇 |
晶体学 | 3篇 |
力学 | 19篇 |
数学 | 4篇 |
物理学 | 22篇 |
出版年
2021年 | 1篇 |
2020年 | 1篇 |
2019年 | 3篇 |
2018年 | 1篇 |
2017年 | 3篇 |
2016年 | 5篇 |
2015年 | 2篇 |
2014年 | 5篇 |
2013年 | 13篇 |
2012年 | 9篇 |
2011年 | 10篇 |
2010年 | 8篇 |
2009年 | 4篇 |
2008年 | 6篇 |
2007年 | 9篇 |
2006年 | 4篇 |
2005年 | 9篇 |
2004年 | 1篇 |
2003年 | 1篇 |
2002年 | 4篇 |
2001年 | 3篇 |
2000年 | 4篇 |
1999年 | 3篇 |
1998年 | 1篇 |
1996年 | 3篇 |
1995年 | 4篇 |
1994年 | 4篇 |
1993年 | 2篇 |
1992年 | 1篇 |
1991年 | 2篇 |
1990年 | 2篇 |
1989年 | 2篇 |
1986年 | 2篇 |
1985年 | 2篇 |
1984年 | 3篇 |
1982年 | 1篇 |
1981年 | 2篇 |
1980年 | 2篇 |
1979年 | 2篇 |
1976年 | 2篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1973年 | 1篇 |
1952年 | 1篇 |
1901年 | 2篇 |
1900年 | 1篇 |
排序方式: 共有153条查询结果,搜索用时 484 毫秒
121.
The trapping and sticking of H and D atoms on the graphite (0001) surface is examined, over the energy range of 0.1-0.9 eV. For hydrogen to chemisorb onto graphite, the bonding carbon must pucker out of the surface plane by several tenths of an angstrom. A quantum approach in which both the hydrogen and the bonding carbon atoms can move is used to model the trapping, and a potential energy surface based on density functional theory calculations is employed. It is found, for energies not too far above the 0.2 eV barrier to chemisorption that a significant fraction of the incident H or D atoms can trap. The forces on the bonding carbon are large, and it can reconstruct within 50 fs or so. After about 100 fs, most of the trapped H atoms scatter back into the gas phase, but the 5%-10% that remain can have lifetimes on the order of a picosecond or more. Calculations of the resonance eigenstates and lifetimes confirm this. An additional lattice degree of freedom is included quantum mechanically and is shown to significantly increase the amount of H that remains trapped after 1 ps. Further increasing the incident energy destabilizes the trapped state, leading to less H remaining trapped at long times. We estimate that for a full dissipative bath, the sticking probabilities should be on the order of 0.1. 相似文献
122.
A very short and efficient synthesis of protected derivatives of APTO and AETD, the complex polyhydroxylated beta-amino acid residues present in microsclerodermins C, D, and E, is described. The targets are obtained in only five steps, in 23% and 16% overall yields, respectively. The key transformation involves the completely diastereoselective two-carbon homologation of appropriately selected intermediate chiral sulfinimines. 相似文献
123.
Joly L Antoine R Broyer M Lemoine J Dugourd P 《The journal of physical chemistry. A》2008,112(5):898-903
Electron detachment from peptide dianions is studied as a function of the laser wavelength. The first step for the detachment is a resonant electronic excitation of the dianions. Electronic excitation spectra are reported for three peptides, including gramicidin. A comparative study of the detachment yield for 13 peptides was performed at 260 nm and at 220 nm. At 260 nm, the detachment yield is mainly driven by the sum of the absorption coefficients of the aromatic amino acids that are contained in the peptide. At 220 nm, no direct relation is observed between the electron photodetachement yields and the sum of absorption efficiencies. At this wavelength, the sequence and the structure of the peptide may have an influence on the photodetachment process. 相似文献
124.
Ventrapati Pavan Kumar Gabin Gulou Pierric Lemoine Bernard Raveau Andrew R. Supka Rabih Al Rahal Al Orabi Marco Fornari Koichiro Suekuni Emmanuel Guilmeau 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(43):15601-15609
Herein, we investigate the Mo and W substitution for Cr in synthetic colusite, Cu26Cr2Ge6S32. Primarily, we elucidate the origin of extremely low electrical resistivity which does not compromise the Seebeck coefficient and leads to outstanding power factors of 1.94 mW m?1 K?2 at 700 K in Cu26Cr2Ge6S32. We demonstrate that the abnormally long iono‐covalent T–S bonds competing with short metallic Cu–T interactions govern the electronic transport properties of the conductive “Cu26S32” framework. We address the key role of the cationic size‐mismatch at the core of the mixed tetrahedral–octahedral complex over the transport properties. Two essential effects are identified: 1) only the tetrahedra that are directly bonded to the [TS4]Cu6 complex are significantly distorted upon substitution and 2) the major contribution to the disorder is localized at the central position of the mixed tetrahedral–octahedral complex, and is maximized for x=1, i.e. for the highest cationic size‐variance, σ2. 相似文献
125.
Viktoria K. Muravieva Dr. Yakov M. Gayfulin Dr. Carmelo Prestipino Dr. Pierric Lemoine Dr. Maxim R. Ryzhikov Dr. Vadim V. Yanshole Dr. Stéphane Cordier Dr. Nikolay G. Naumov 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(66):15040-15045
Influence of the metal core composition and geometry on the structure, spectroscopic properties and redox potentials was investigated for the first time for heterometallic (Re/Mo)6 octahedral clusters. The discrete anionic clusters [Re6-xMoxSe8(CN)6]n− (x=2, 3; n=4, 5) were obtained as individual salts. Their isomeric composition and bond-length distribution were inspected using a combination of single-crystal X-ray structure analysis, NMR, EXAFS, and DFT calculations. 相似文献
126.
Jordan Ledig Eric Faudot Jérôme Moritz Stéphane Heuraux Nicolas Lemoine Stéphane Devaux 《等离子体物理论文集》2020,60(10):e202000072
Potential and density structures in the vicinity of an radio frequency (RF) electrode/antenna in a magnetized plasma are investigated using an RF-compensated cylindrical Langmuir probe. These measurements were performed in the ALINE plasma device in which only electrons can be considered well magnetized. Very precise 2-D maps of the plasma parameters are drawn thanks to a 3-D automatic manipulator on which the probe is mounted. The effect of the tilted magnetic angle between the RF-biased surface and the magnetic lines is also studied thanks to a tilting electrode. Comparison of several simplistic models with the experiments proved the reliability of simple Langmuir probe measurements in such an RF and magnetized environment (space potential vs. tilting angle of the antenna with respect to magnetic field lines and recovery of the floating potential structure using measured currents). A fluid model based on total current density and ion diffusion equations over the biased flux tube provides the same density structures in front of the electrode as the measurements. Those density structures display a “bunny ears” shape and can be explained using transverse RF and collisional current behaviour: In front of the antenna, the transverse ion currents deplete the magnetized flux tube, while at the edge of the biased flux tube, the same currents increase the density. 相似文献
127.
128.
Electron photodetachment of trapped doubly deprotonated angiotensin peptides. UV spectroscopy and radical recombination 总被引:1,自引:0,他引:1
R. Antoine L. Joly A. R. Allouche M. Broyer J. Lemoine Ph. Dugourd 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2009,51(1):117-124
Trapped doubly deprotonated peptides are subjected to electron detachment when irradiated by a UV light. Electron photodetachment
experiments as a function of the laser wavelength and laser fluence have been performed on two variants of angiotensin. The
electron detachment yield was used to monitor the excited electronic spectrum of the trapped ions. Furthermore, the electron
loss leads to the formation of radical ions. The radical recombination after collision activation is discussed. 相似文献
129.
130.
N. R. Lee-Hone P. Lemoine D. H. Ryan B. Malaman A. Vernière G. Le Caër 《Hyperfine Interactions》2014,226(1-3):309-319
We present a simple model based on an isotropic transferred hyperfine field to calculate the transferred hyperfine field distribution at the Sn site of the antiferromagnetic CeScSi-type RMgSn compounds. The calculations correctly reproduce the main features observed in NdMgSn, TbMgSn, DyMgSn, HoMgSn, and ErMgSn. The transferred hyperfine field distributions are remarkably sensitive to the complex magnetic structures in the RMgSn compounds, and can be used to discriminate between competing magnetic structure models. 相似文献