全文获取类型
收费全文 | 637篇 |
免费 | 12篇 |
国内免费 | 5篇 |
专业分类
化学 | 491篇 |
晶体学 | 9篇 |
力学 | 3篇 |
数学 | 28篇 |
物理学 | 123篇 |
出版年
2022年 | 5篇 |
2021年 | 9篇 |
2020年 | 4篇 |
2019年 | 10篇 |
2018年 | 8篇 |
2017年 | 8篇 |
2016年 | 3篇 |
2015年 | 12篇 |
2014年 | 17篇 |
2013年 | 36篇 |
2012年 | 36篇 |
2011年 | 35篇 |
2010年 | 16篇 |
2009年 | 19篇 |
2008年 | 35篇 |
2007年 | 50篇 |
2006年 | 22篇 |
2005年 | 31篇 |
2004年 | 30篇 |
2003年 | 29篇 |
2002年 | 38篇 |
2001年 | 9篇 |
2000年 | 11篇 |
1999年 | 8篇 |
1998年 | 7篇 |
1997年 | 8篇 |
1995年 | 8篇 |
1994年 | 3篇 |
1993年 | 5篇 |
1992年 | 7篇 |
1991年 | 6篇 |
1990年 | 10篇 |
1989年 | 7篇 |
1988年 | 9篇 |
1986年 | 4篇 |
1985年 | 7篇 |
1984年 | 11篇 |
1983年 | 5篇 |
1982年 | 9篇 |
1981年 | 6篇 |
1979年 | 6篇 |
1978年 | 10篇 |
1977年 | 3篇 |
1976年 | 5篇 |
1975年 | 6篇 |
1974年 | 4篇 |
1973年 | 4篇 |
1968年 | 2篇 |
1967年 | 7篇 |
1965年 | 2篇 |
排序方式: 共有654条查询结果,搜索用时 15 毫秒
101.
Turbulent transport near the critical gradient in toroidal plasmas is studied based on global Landau-fluid simulations and an extended predator-prey theoretical model of ion temperature gradient turbulence. A new type of intermittent transport associated with the emission and propagation of a geodesic acoustic mode (GAM) is found near the critical gradient regime, which is referred to as GAM intermittency. The intermittency is characterized by new time scales of trigger, damping, and recursion due to GAM damping. During the recursion of intermittent bursts, stationary zonal flow increases with a slow time scale due to the accumulation of undamped residues and eventually quenches the turbulence, suggesting that a nonlinear upshift of the critical gradient, i.e., Dimits shift, is established through such a dynamical process. 相似文献
102.
Miki Yumoto Takahiro Tamura Taketomo Sato Hideki Hasegawa 《Superlattices and Microstructures》2003,34(3-6):485
In view of applications to hexagonal binary decision diagram (BDD) LSIs, a first attempt is made to form quantum BDD node switches on selectively grown (SG) embedded quantum wires (QWRs) by molecular beam epitaxy (MBE). SG branch switches controlled by a Schottky wrap gate (WPG) were successfully fabricated by MBE growth and subsequent device processing. Gate control characteristics were studied by gate-dependent Shubnikov–de-Haas measurements, and the behavior was found to be similar to that of devices fabricated on wires by etching. The switch exhibited clear conductance quantization at low temperature, and temperature dependence of the voltage slope of conductance jump was clarified. A Y-branch BDD node device using two SG branch switches was successfully fabricated, and realized clear path switching characteristics. 相似文献
103.
Electrical conducitivities of both ferricytochrome c and ferrocytochrome c anhydrous films were measured at physiological temperatures. A film-casting method was applied to prepare the films. Rather low values of resistivities (55°C) of 6.5 × 1010 Ω cm for ferrocytochrome c in comparison with the previously reported value of 1011 Ω cm (127°C) were obtained. Apparent activation energies for the above conductivities, 0.6 eV, were the same in both samples. 相似文献
104.
Yoshinori Fujimoto Miki Kimura Akihiro Takasu Fathy A.M. Khalifa Masuo Morisaki Nobuo Ikekawa 《Tetrahedron letters》1984,25(14):1501-1504
Deuterated stigmasterols (10, 11 and 12) were chemically synthesized and fed to silk-worm larvae. GC-MS analysis of the metabolites, cholesterol (4) and desmosterol (6), indicates the migration of 25-hydrogen to C-24 position during stigmasterol dealkylation. 22,24(28)-Dienes(8a and 8b) were shown to be converted to 22,24-diene (5), desmosterol and cholesterol. 相似文献
105.
106.
107.
108.
109.
Low-energy electron energy loss spectra in theC(1s) core electron excitation region have been measured in diamond, graphite and glassy carbon in the non-differentiated form. The background subtractedN(E) spectrum has been proved to reflect the density-of-states (DOS) of the conduction band well, and the conduction band structures of these materials have been elucidated. The energy positions of the symmetry points in their conduction bands have been determined from the second-derivative spectra, which were obtained by numerical differentiation of the measuredN(E) spectra. 相似文献
110.