全文获取类型
收费全文 | 502781篇 |
免费 | 5244篇 |
国内免费 | 1657篇 |
专业分类
化学 | 252826篇 |
晶体学 | 8241篇 |
力学 | 23959篇 |
综合类 | 8篇 |
数学 | 60656篇 |
物理学 | 163992篇 |
出版年
2021年 | 4182篇 |
2020年 | 4552篇 |
2019年 | 5160篇 |
2018年 | 6960篇 |
2017年 | 7113篇 |
2016年 | 9962篇 |
2015年 | 5838篇 |
2014年 | 9728篇 |
2013年 | 23396篇 |
2012年 | 17620篇 |
2011年 | 21505篇 |
2010年 | 15661篇 |
2009年 | 15563篇 |
2008年 | 19455篇 |
2007年 | 19402篇 |
2006年 | 18075篇 |
2005年 | 15975篇 |
2004年 | 14864篇 |
2003年 | 13146篇 |
2002年 | 13107篇 |
2001年 | 15338篇 |
2000年 | 11585篇 |
1999年 | 9099篇 |
1998年 | 7615篇 |
1997年 | 7381篇 |
1996年 | 7010篇 |
1995年 | 6224篇 |
1994年 | 6127篇 |
1993年 | 6086篇 |
1992年 | 6561篇 |
1991年 | 6850篇 |
1990年 | 6515篇 |
1989年 | 6370篇 |
1988年 | 6192篇 |
1987年 | 6215篇 |
1986年 | 5817篇 |
1985年 | 7670篇 |
1984年 | 7902篇 |
1983年 | 6427篇 |
1982年 | 6678篇 |
1981年 | 6397篇 |
1980年 | 6203篇 |
1979年 | 6569篇 |
1978年 | 6609篇 |
1977年 | 6586篇 |
1976年 | 6667篇 |
1975年 | 6193篇 |
1974年 | 6166篇 |
1973年 | 6256篇 |
1972年 | 4422篇 |
排序方式: 共有10000条查询结果,搜索用时 484 毫秒
911.
The method that we previously developed for going over from double volume integrals to double surface integrals in calculating the Coulomb energy of nuclei that have a sharp surface is generalized to the case of nuclei where the range of nuclear forces is finite and where the nuclear surface is diffuse. New formulas for calculating the Coulomb and the nuclear energy of deformed nuclei are obtained within this approach. For a spherically symmetric nucleus, in which case there is an analytic solution to the problem in question, the results are compared with those that are quoted in the literature, and it is shown that the respective results coincide identically. A differential formulation of the method developed previously by Krappe, Nix, and Sierk for going over from double volume integrals to double surface integrals is proposed here on the basis of the present approach. 相似文献
912.
Yu. B. Bolkhovityanov S. Ts. Krivoshchapov A. I. Nikiforov B. Z. Ol’shanetskii O. P. Pchelyakov L. V. Sokolov S. A. Teys 《Physics of the Solid State》2004,46(1):64-66
Different techniques for the fabrication of structures containing ensembles of ultrasmall germanium nanoclusters distributed with a high density over the substrate surface are discussed. How to control the morphology and ordering of these ensembles is also discussed. 相似文献
913.
B. P. Sorokin D. A. Glushkov L. N. Bezmaternykh V. L. Temerov I. A. Gudim K. S. Aleksandrov 《Physics of the Solid State》2004,46(3):458-461
Single crystals of lead gallium germanate Pb3Ga2Ge4O14 are grown from their own solution melts. The propagation of bulk acoustic waves is investigated, and the elastic, piezoelectric, and dielectric constants are calculated. The temperature dependences of the dielectric constants of this compound are analyzed. 相似文献
914.
E. A. Ekimov E. L. Gromnitskaya D. A. Mazalov A. F. Pal’ V. V. Pichugin S. Gierlotka B. Palosz J. A. Kozubowski 《Physics of the Solid State》2004,46(4):755-757
Superhard nanodiamond-SiC ceramics are prepared by infiltrating liquid Si into porous nanodiamond compacts under pressure.
Synthesized samples are 2.2 mm thick and 3–4 mm in diameter. The effect of particle size of dynamically synthesized nanodiamond
powders on silicon infiltration and SiC phase formation is studied. It is established that silicon does not penetrate into
the pores of nanodiamond powders if the original particle size is smaller than 0.5–1.0 μm. The critical pore size for infiltration
is 100–200 nm. A study of the microstructure of the samples showed the presence of the nanometer-and submicron-scale SiC phase.
The ultrasound velocities are measured in the prepared compacts, and the elastic moduli are calculated.
__________
Translated from Fizika Tverdogo Tela, Vol. 46, No. 4, 2004, pp. 734–736.
Original Russian Text Copyright ? 2004 by Ekimov, Gromnitskaya, Mazalov, Pal’, Pichugin, Gierlotka, Palosz, Kozubowski. 相似文献
915.
V. V. Popov T. V. Teperik O. V. Polischuk X. G. Peralta S. J. Allen N. J. M. Horing M. C. Wanke 《Physics of the Solid State》2004,46(1):153-156
The terahertz absorption spectra of plasmon modes in a grid-gated double-quantum-well field-effect transistor structure is analyzed theoretically and numerically using the scattering matrix approach and is shown to faithfully reproduce strong resonant features of recent experimental observations of terahertz photo-conductivity in such a structure. 相似文献
916.
917.
The states of electron-hole pairs in spherical silicon nanocrystals are theoretically studied using the “multiband” effective-mass approximation in the limit of an infinitely high potential barrier at the boundary. The degeneracy of the states at the top of the valence band is taken into account in the spherical approximation, and the ellipsoidal character of the electronic spectrum in the conduction band is allowed for. Coulomb interaction-induced corrections to the energy of an electron-hole pair are found. 相似文献
918.
Amorphous silver, copper, gold, and iron films of a thickness between 6 and 350 nm are grown on polymeric substrates by vacuum
evaporation. The nanostructure of the films is investigated. The dependence of the conductivity on the film thickness is obtained,
and a correlation between the surface morphology and the conductivity is established. 相似文献
919.
The integral characteristics of magnetization switching in amorphous gadolinium-cobalt films with perpendicular anisotropy
are studied by visualizing the domain structure and measuring magnetooptic hysteresis loops. The films have a radial gradient
of magnetic properties that is due to a spatially nonuniform thermal field. Magnetization switching in those film areas where
the domain wall motion depends only on the coercive force is simulated in simple terms. In a first approximation, local events
of magnetization switching are shown to take place independently of each other and the net hysteresis loop can be represented
as a sum of the local loops. 相似文献
920.
Technical Physics - Analytical models for the magnetization vector field B m in a uniaxial ferromagnetic film are studied. Some of them are found to closely approximate B m even if the quality... 相似文献