全文获取类型
收费全文 | 713587篇 |
免费 | 6461篇 |
国内免费 | 1689篇 |
专业分类
化学 | 358301篇 |
晶体学 | 10612篇 |
力学 | 36033篇 |
综合类 | 26篇 |
数学 | 99118篇 |
物理学 | 217647篇 |
出版年
2021年 | 5843篇 |
2020年 | 6485篇 |
2019年 | 7306篇 |
2018年 | 13698篇 |
2017年 | 14080篇 |
2016年 | 15663篇 |
2015年 | 7948篇 |
2014年 | 12717篇 |
2013年 | 29816篇 |
2012年 | 24820篇 |
2011年 | 33503篇 |
2010年 | 23688篇 |
2009年 | 23661篇 |
2008年 | 30639篇 |
2007年 | 32448篇 |
2006年 | 22985篇 |
2005年 | 23587篇 |
2004年 | 20518篇 |
2003年 | 19100篇 |
2002年 | 17802篇 |
2001年 | 18686篇 |
2000年 | 14607篇 |
1999年 | 11158篇 |
1998年 | 9467篇 |
1997年 | 9313篇 |
1996年 | 8845篇 |
1995年 | 8043篇 |
1994年 | 7942篇 |
1993年 | 7569篇 |
1992年 | 8467篇 |
1991年 | 8786篇 |
1990年 | 8495篇 |
1989年 | 8408篇 |
1988年 | 8284篇 |
1987年 | 8116篇 |
1986年 | 7754篇 |
1985年 | 9871篇 |
1984年 | 10218篇 |
1983年 | 8440篇 |
1982年 | 8783篇 |
1981年 | 8369篇 |
1980年 | 7916篇 |
1979年 | 8654篇 |
1978年 | 8905篇 |
1977年 | 8806篇 |
1976年 | 8636篇 |
1975年 | 8190篇 |
1974年 | 7995篇 |
1973年 | 8193篇 |
1972年 | 5882篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
971.
R. G. Zakinyan 《Technical Physics》2004,49(9):1110-1115
The motion of the front of crystallization and the growth of a film at the surface of a plate are analyzed in the case of
a laminar and in the case of a turbulent flow mode. Conditions are determined under which there occurs a transition from a
matt inhomogeneous structure to a transparent homogeneous structure of ice. It is shown that, for a film to be steadily preserved
at the plate surface, the film thickness must be larger than a critical equilibrium-thickness value h
b.c, in which case a transparent homogeneous structure of ice is formed. Otherwise, the film at the plate surface is unstable
and disappears in the course of time. The icing of aircrafts is the most important application of the results obtained in
this study. 相似文献
972.
Influence of the skin effect on the absorption of electromagnetic radiation by a fine metal particle
The cross section of absorption of electromagnetic radiation by a fine spherical metal particle is calculated. The influence of the skin effect on the absorption cross-section is estimated for an arbitrary ratio between the free path and size of the particle. The results of this work are compared with those obtained earlier in the framework of classical electrodynamics. It is shown that taking into account the kinetic effects modifies essentially the known data for the skin effect in a spherical particle. 相似文献
973.
E. L. Pankratov 《Technical Physics》2004,49(1):114-118
The establishment of the steady-state dopant profile in a medium with a time-variable diffusion coefficient is considered
within the approach proposed previously for estimating mass-and heat-transfer time characteristics. It is shown that the time
it takes for the equilibrium concentration to set in may be increased or decreased by appropriately choosing the law of variation
of the diffusion coefficient. 相似文献
974.
Technical Physics - An analytical expression for the generatrix of the shape of a nonlinearly vibrating charged drop of a perfect incompressible conducting fluid immersed in an ideal incompressible... 相似文献
975.
A theory of a planar disk-shaped RF plasma source under anomalous skin effect conditions is developed. In the absence of an external magnetic field, such conditions are satisfied for transverse electromagnetic waves with phase velocities below the electron thermal velocity, and, in the presence of this field, they are satisfied for electron cyclotron waves with frequencies corresponding to the resonant absorption line. For each of these cases, the RF field power deposited in a plasma with given parameters is determined and the equivalent plasma resistance is calculated. 相似文献
976.
S. N. Kulkov 《Russian Physics Journal》2004,47(9):954-963
The special features of the structure and phase composition of nanocrystalline zirconia-based powders subjected to shock-wave treatment are studied. The investigations show that zirconia with small amounts of yttria and/or alumina is in nanocrystalline and quasi-amorphous states representing a nonequilibrium solid solution of ZrO2 (Y, Al) and that an increase in the monoclinic phase abundance is associated with a reduction in the critical size of tetragonal crystallites due to an accumulation of lattice microdistortions. The monoclinic phase in powders with yttria and alumina additions is not formed even with shock compression at pressures up to 20 GPa. This is attributed to the fact that the resultant lattice microdistortion level is inadequate to destabilize the nanocrystalline tetragonal phase. Relaxation of microdistortions on annealing causes the critical size of tetragonal crystallites to increase. As this takes place, the monoclinic phase is converted into the tetragonal one.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 9, pp. 61–70, September, 2004. 相似文献
977.
Dineykhan M. Zhaugasheva S. A. Kozhamkulov T. A. Petrov E. V. 《Russian Physics Journal》2004,47(12):1250-1260
The mass spectrum of a coupled state is analytically determined. The mechanism of production of a constituent mass of particles forming a coupled state is explained. The change of the coupled state and constituent particle component masses attendant to changes of the coupling constant is analyzed. The mass spectrum of a two-gluon glueball is determined with allowance for spin-orbital and spin-spin interactions.__________Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 12, pp. 33–41, December, 2004. 相似文献
978.
Oksengendler B. L. Karimov M. Yunusov M. C. Karakhodzhaev A. K. 《Russian Physics Journal》2004,47(7):790-791
Russian Physics Journal - 相似文献
979.
A semiempirical model is proposed for the calculation of electrical, magnetic and thermal parameters of the plasma of a high-frequency induction discharge. The model is based on solving a system of two-dimensional Maxwell equations written for a cylindrical coordinate system. 相似文献
980.
V. S. Gorelik P. P. Sverbil' A. B. Fadyushin V. V. Vasil'ev 《Journal of Russian Laser Research》2004,25(1):54-63
A possibility of application of semiconductor lasers of the visible range as exciting sources for Raman spectroscopy is studied. An experimental set-up for measuring Raman spectra of polycrystalline dielectrics and broad-gap semiconductors excited by a semiconductor laser with a wavelength of 640 nm was created. The conditions under which the spectral width of the lasing line of a semiconductor laser was within 10-3 cm-1 in the continuous mode with a power of 10 mW are realized. The characteristics of various types of exciting sources used in Raman spectroscopy are compared. The results of studies of the characteristic Raman spectra excited with a semiconductor laser in polycrystalline sulfur are presented. 相似文献