全文获取类型
收费全文 | 102篇 |
免费 | 1篇 |
专业分类
化学 | 52篇 |
数学 | 3篇 |
物理学 | 48篇 |
出版年
2023年 | 1篇 |
2022年 | 1篇 |
2020年 | 2篇 |
2016年 | 2篇 |
2013年 | 1篇 |
2012年 | 4篇 |
2011年 | 2篇 |
2010年 | 2篇 |
2008年 | 3篇 |
2006年 | 4篇 |
2005年 | 3篇 |
2004年 | 5篇 |
2003年 | 3篇 |
2002年 | 3篇 |
2000年 | 1篇 |
1998年 | 2篇 |
1996年 | 2篇 |
1995年 | 7篇 |
1994年 | 2篇 |
1992年 | 5篇 |
1991年 | 3篇 |
1990年 | 1篇 |
1989年 | 5篇 |
1988年 | 3篇 |
1987年 | 2篇 |
1986年 | 4篇 |
1985年 | 6篇 |
1984年 | 3篇 |
1983年 | 3篇 |
1982年 | 1篇 |
1981年 | 2篇 |
1980年 | 2篇 |
1979年 | 1篇 |
1978年 | 2篇 |
1977年 | 3篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1973年 | 5篇 |
排序方式: 共有103条查询结果,搜索用时 15 毫秒
61.
62.
E.A. Zibik L.R. Wilson R.P. Green G. Bastard R. Ferreira P.J. Phillips D.A. Carder J-P.R. Wells M.S. Skolnick J.W. Cockburn M.J. Steer M. Hopkinson 《Physica E: Low-dimensional Systems and Nanostructures》2005,26(1-4):408
Polaron relaxation processes in a series of n-type InAs quantum dots (QDS) have been investigated using energy-dependent far-infrared pump–probe spectroscopy. For energies up to 53 meV, polarons decay to 2 longitudinal acoustic phonons; above this energy additional decay channels open resulting in a reduction of the decay time. Inter-state transfer has been observed between closely spaced p-like excited states, with the measured transfer times in good agreement with calculations assuming acoustic phonon assisted transfer. Finally, for QDs containing 2 electrons we observe evidence of a spin-flip process resulting in long (700 ps) relaxation times. 相似文献
63.
G. Bastard 《Superlattices and Microstructures》1985,1(3):265-273
We present the results of the calculations of some electronic properties of semiconductor quantum wells and superlattices. The review includes the superlattice band structure and the quantum well bound energy levels; the virtual bound states of semiconductor quantum wells and their influence on the energy spectrum of separate confinement heterostructures. Finally the perturbation of quantum well bound states and exciton states by a static electric field applied parallel to the growth axis is considered. 相似文献
64.
We have calculated the energy and lineshape of the 1s → 2px,y transition for a hydrogenic impurity located in a quantum well. Due to the dependence of the transition energy on the impurity location, the absorption lineshape is very sensitive to the doping profile. The spectrum, in general, exhibits two peaks, arising from impurities located near the center and the edges of the well. 相似文献
65.
Abdelmaula Aboulaich Florent Robert Pierre Emmanuel Lippens Laurent Aldon Josette Olivier-Fourcade Patrick Willmann Jean-Claude Jumas 《Hyperfine Interactions》2006,167(1-3):733-738
Sn-based composite materials were synthetized by a conventional melt-quenching method, and studied by X-ray diffraction, electrochemistry and in situ 119Sn Mösssbauer spectroscopy. Tin was dispersed ex situ into a matrix formed from B2O3:P2O5. XRD and 119Sn Mössbauer spectroscopy show the formation of an interface between the active species (Sn0) and the matrix. This amorphous interface acts as a “buffer-zone” which compensates volume changes during the tin–lithium alloy formation and avoids aggregation of tin particles. 相似文献
66.
67.
68.
69.
Walter G. Rothschild Janine Soussen-Jacob Josette Vincent-Geisse 《Chemical physics letters》1983,96(1):43-46
A model of vibrational dephasing with motional narrowing by the librational motions of the molecules in their cages is tested on the example of the ν6 degenerate infrared fundamental of liquid CD3l at room temperature. 相似文献
70.
Borden MA Martinez GV Ricker J Tsvetkova N Longo M Gillies RJ Dayton PA Ferrara KW 《Langmuir : the ACS journal of surfaces and colloids》2006,22(9):4291-4297
In the design of lipid-coated microbubble ultrasound contrast agents for molecular imaging and targeted drug delivery, the surface distribution of the shell species is important because it dictates such properties as ligand location, brush coverage, and amount of drug loading. We used a combination of spectroscopy and microscopy techniques to test the prevailing notion that the main phosphatidyl choline (PC) and lipopolymer species are completely miscible within the monolayer shell. NMR spectroscopy showed that the shell composition is roughly equivalent to the bulk lipid ratio. FTIR spectroscopy showed a sharp melting peak corresponding to the main phase-transition temperature of the main PC species, with no observed pretransitions while scanning from room temperature, indicating a single PC-rich ordered phase. Electron and fluorescence microscopy showed a heterogeneous microstructure with dark (ordered) domains and bright (disordered) regions. Domain formation was thermotropic and reversible. Fluorescent labeling of the lipopolymer following shell formation showed that it partitions preferentially into the disordered interdomain regions. The ordered domains, therefore, are composed primarily of PC, and the disordered interdomain regions are enriched in lipopolymer. Phase heterogeneity was observed at all lipopolymer concentrations (0.5 to 20 mol %), and the degree of phase separation increased with lipopolymer content. The composition and temperature dependence of the microstructure indicates that phase separation is driven thermodynamically rather than being a kinetically trapped relic of the shell-formation process. The overall high variation in microstructure, including the existence of anomalous three-phase coexistence, highlights the nonequilibrium (history-dependent) nature of the monolayer shell. 相似文献