全文获取类型
收费全文 | 181篇 |
免费 | 2篇 |
专业分类
化学 | 38篇 |
物理学 | 145篇 |
出版年
2021年 | 1篇 |
2020年 | 1篇 |
2018年 | 4篇 |
2017年 | 2篇 |
2016年 | 2篇 |
2015年 | 1篇 |
2014年 | 4篇 |
2013年 | 1篇 |
2012年 | 6篇 |
2011年 | 7篇 |
2010年 | 3篇 |
2009年 | 2篇 |
2008年 | 6篇 |
2007年 | 13篇 |
2006年 | 13篇 |
2005年 | 3篇 |
2004年 | 8篇 |
2003年 | 4篇 |
2002年 | 4篇 |
2001年 | 6篇 |
2000年 | 7篇 |
1999年 | 3篇 |
1998年 | 11篇 |
1997年 | 4篇 |
1996年 | 9篇 |
1995年 | 1篇 |
1994年 | 7篇 |
1993年 | 11篇 |
1992年 | 8篇 |
1991年 | 6篇 |
1990年 | 5篇 |
1989年 | 1篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1977年 | 1篇 |
1976年 | 3篇 |
1975年 | 1篇 |
1974年 | 3篇 |
1964年 | 1篇 |
1958年 | 1篇 |
1956年 | 2篇 |
1933年 | 1篇 |
排序方式: 共有183条查询结果,搜索用时 15 毫秒
51.
52.
An experimental configuration based on gated, double boundary GaAs/AlGaAs devices provides the first demonstration of dual distinct, tunable Hall resistances in the same sample over the weak- and strongmagnetic field limits, including the simultaneous observability of dual quantized Hall effects of dissimilar filling factors. These experiments suggest that the ordinary Hall resistance examined in experiment is essentially a topological resistance determined by connectivity, which need not reflect all “local” values of the off-diagonal resistivity, θ M ρ xy . 相似文献
53.
M. N. Khannanov I. V. Kukushkin S. I. Gubarev J. Smet K. von Klitzing W. Wegscheider C. Gerl 《JETP Letters》2007,85(5):242-245
The dependence of the heavy-hole cyclotron mass in GaAs(001) quantum wells on the 2D-hole density has been measured by the optical detection method for resonance microwave by-absorption. A significant increase (almost doubling) has been observed in the cyclotron mass of heavy holes with an increase in the charge carrier density from 1.2 × 1010 cm?2 to 1.3 × 1011 cm?2. 相似文献
54.
55.
Photoconductivity is observed in n-channel inversion Si MOSFETS at 4.2 K at infrared frequencies up to 700 cm?1. Two groups of sharp lines of opposite sign are observed in the regions of 300 and 650 cm?1 together with a continuum of transitions starting at ~ 350 cm?1. The sharp lines are interpreted as bound transitions from shallow neutral phosphorous donors and boron acceptors on either side of the depletion layer. The angular dependence of the Zeeman splitting of the sharp lines demonstrates that the normal 90° symmetry of the 100 surface is lifted for devices with thin metal gates due to the presence of a strong unixial stress component. 相似文献
56.
Shubnikov-de Haas oscillations have been studied for (110) and (111) n-type silicon inversion layers. The measured cyclotron masses mc = (0.38 ± 0.03)m0 and mc = (0.40 ± 0.03)m0 for (110) and (111) planes, respectively, are larger than theoretically predicted values. The experimental valley degeneracy factor gv = 2 ± 0.2 for both orientations is also at variance with self consistent calculations. The electronic g-factor depends on the surface carrier concentration and is enhanced over its bulk value. There was no evidence for the occupation of other subbands. 相似文献
57.
Shvarchuck I Buggle Ch Petrov DS Dieckmann K Zielonkowski M Kemmann M Tiecke TG von Klitzing W Shlyapnikov GV Walraven JT 《Physical review letters》2002,89(27):270404
We report the formation of Bose-Einstein condensates into nonequilibrium states. Our condensates are much longer than equilibrium condensates with the same number of atoms, show strong phase fluctuations, and have a dynamical evolution similar to that of quadrupole shape oscillations of regular condensates. The condensates emerge in elongated traps as the result of local thermalization when the nucleation time is short compared to the axial oscillation time. We introduce condensate focusing as a new method to extract the phase-coherence length of Bose-Einstein condensates. 相似文献
58.
The impact of the cononsolvency effect on poly (N-isopropylacrylamide) based microgels at interfaces
Marcel Richter Melanie Hunnenmörder Regine V. Klitzing 《Colloid and polymer science》2014,292(10):2439-2452
The paper addresses the effect of solid interfaces on the cononsolvency effect for poly(N-iso propylacrylamide) based microgels containing different contents of the co-monomer allyl acetic acid (AAA). The cononsolvency effect is studied by dynamic light scattering (DLS) in solution and with atomic force microscopy (AFM) at surfaces against different mixtures of water and organic solvent (ethanol, iso-propanol, and tetrahydrofuran). For the studies at interfaces, the microgels are spin coated on silicon wafers that are precoated with poly(allylamine hydrochloride) (PAH). The minimum in particle volume due to cononsolvency shows a pronounced shift from 10–20 % of organic solvent to 40–50 % after deposition at the Si/PAH wafer. The strong shift indicates an increase of water to organic solvent ratio within the gel at the surface with respect to the bulk solution. In order to understand the increase of water to organic solvent ratio, shrinking/reswelling AFM experiments for different spin-coating conditions and under ambient conditions are carried out. Spin coating from water instead from different solvent mixtures has no effect on the cononsolvency. In ambient conditions, the cononsolvency effect disappears 相似文献
59.
60.
O. V. Volkov V. E. Zhitomirskii I. V. Kukushkin K. von Klitzing K. Eberl 《JETP Letters》1997,65(1):38-44
The recombination radiation spectra of two-dimensional electrons in an asymmetrically doped GaAs/AlGaAs quantum well are investigated
at different temperatures and laser-excitation energies. At low temperatures and in high magnetic fields the recombination
lines of the electrons from completely filled Landau levels are split into narrow sublevels. It is shown that this fine structure
of the Landau levels is due to the presence of excitonic effects in the initial and final states of the photoexcited system.
It is demonstrated that the recombination process is accompanied by the excitation of intersubband and cyclotron magnetoplasma
modes.
Pis’ma Zh. éksp. Teor. Fiz. 65, No. 1, 38–43 (10 January 1997) 相似文献