全文获取类型
收费全文 | 700425篇 |
免费 | 21917篇 |
国内免费 | 1729篇 |
专业分类
化学 | 391835篇 |
晶体学 | 10091篇 |
力学 | 33301篇 |
综合类 | 26篇 |
数学 | 85603篇 |
物理学 | 203215篇 |
出版年
2021年 | 7982篇 |
2020年 | 10412篇 |
2019年 | 9258篇 |
2018年 | 11548篇 |
2017年 | 10254篇 |
2016年 | 18353篇 |
2015年 | 12321篇 |
2014年 | 16853篇 |
2013年 | 34204篇 |
2012年 | 25310篇 |
2011年 | 27872篇 |
2010年 | 22910篇 |
2009年 | 22717篇 |
2008年 | 26124篇 |
2007年 | 25624篇 |
2006年 | 22981篇 |
2005年 | 20606篇 |
2004年 | 19025篇 |
2003年 | 17263篇 |
2002年 | 16985篇 |
2001年 | 18635篇 |
2000年 | 14410篇 |
1999年 | 11159篇 |
1998年 | 9467篇 |
1997年 | 9365篇 |
1996年 | 8773篇 |
1995年 | 8075篇 |
1994年 | 7943篇 |
1993年 | 7692篇 |
1992年 | 8495篇 |
1991年 | 8788篇 |
1990年 | 8480篇 |
1989年 | 8407篇 |
1988年 | 8303篇 |
1987年 | 8141篇 |
1986年 | 7753篇 |
1985年 | 9872篇 |
1984年 | 10214篇 |
1983年 | 8450篇 |
1982年 | 8816篇 |
1981年 | 8414篇 |
1980年 | 7985篇 |
1979年 | 8717篇 |
1978年 | 8973篇 |
1977年 | 9046篇 |
1976年 | 8892篇 |
1975年 | 8531篇 |
1974年 | 8328篇 |
1973年 | 8359篇 |
1972年 | 6157篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
New effects are observed wherein the internal structure of the domain walls in a thin magnetic iron garnet film are modified
by the action of focused laser radiation. A single laser pulse with increasing power gives rise to the following: 1) displacement
of vertical Bloch lines in a domain wall; 2) generation of a pair of vertical Bloch lines on initially line-free walls; and,
3) an irreversible change in shape of a domain wall and the domain structure as a whole. The mechanism leading to the generation
and displacement of Bloch lines is connected with the motion of domain walls which is induced by a local change in the distribution
of demagnetizing fields as a result of a heating-induced decrease of the magnetization in the focal spot of the laser radiation.
Pis’ma Zh. éksp. Teor. Fiz. 66, No. 6, 398–402 (25 September 1997) 相似文献
992.
The one-loop self-energy correction to the hyperfine splitting of the 1 s and 2 s states of hydrogenlike ions is calculated for both point and finite nuclei. The results of the calculation are combined with
other corrections to find the ground state hyperfine splitting in lithiumlike 209Bi80+ and 165Ho64+.
Pis’ma Zh. éksp. Teor. Fiz. 66, No. 1, 19–22 (10 July 1997)
Published in English in the original Russian journal. Edited by Steve Torstveit. 相似文献
993.
The diffuse scattering of x rays in a four-layer waveguide-type heterostructure is investigated. The dynamic enhancement of
diffuse scattering is detected experimentally in regions corresponding to the excitation of waveguide modes for both the incident
and scattered waves.
Pis’ma Zh. éksp. Teor. Fiz. 66, No. 4, 219–223 (25 August 1997) 相似文献
994.
995.
Luminescence properties of anodic aluminum oxide films with organic luminophores embedded into pores
V. V. Gruzinskii A. V. Kukhto A. M. Mozalev V. F. Surganov 《Journal of Applied Spectroscopy》1997,64(4):497-502
Luminescence properties of porous anodic aluminum oxide films formed in a 0.6 M solution of citric acid and luminescence of
paraterphenyl, perylene, coumarin 7, and rhodamine 6G dyes adsorbed by the films are investigated. The nature of emitting
centers in anodic aluminum oxide is revealed. Intense photoluminescence of all tested dyes embedded into pores of anodic aluminum
oxide has been found. A redshift of fluorescence spectra of dyes adsorbed by the matrix and emergence of an additional longwave
band have been detected. Data obtained can be used in developing new thin-film luminescent coatings for future applications
in optoelectronics and molecular electronics.
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 64, No 4, pp. 483–488, July–August, 1997. 相似文献
996.
I. Peshko G. Galich M. Lopiychuk A. Khizhnyak V. Nakvasuk 《Optics & Laser Technology》1997,29(4):211-215
A laser system containing four CW Nd:YAG double-rod lasers, transforming optics and a fibre with input-output optics has been designed and investigated. It is shown that reduction of the beam parameter product of the non-Gaussian beams in the image space of the lens has made it possible to collect the emission of four lasers to the same fibre. Independent laser operation has provided the output power control in the range of 10–900 W with a stable light spot size on the input end of the fibre. 相似文献
997.
998.
N. P. Venediktov M. Yu. Glyavin V. E. Zapevalov A. N. Kuftin A. S. Postnikova M. V. Yulpatova 《Radiophysics and Quantum Electronics》1997,40(4):336-342
A scheme for automated study of current-voltage characteristics of gyroresonance devices is developed. The effective emission
spread at the cathodes of powerful gyrotrons is studied by analysis of current-voltage characteristics. Experimental data
on the effective emission spread parameter for different modes are given. The permissible emission spread at the cathodes
of powerful gyrotrons is estimated, and the dependence of the electron beam parameters on the cathode emission spread is presented.
A complex measurement technique showing the contribution of different physical mechanisms to the cathode emission spread is
proposed.
Institute of Applied Physics, Russian Academy of Sciences, Nizhny Novgorod, Russia. Translated from Izvestiya Vysshikh Uchebnykh
Zavedenii, Radiofizika, Vol. 40, No. 4, pp. 506–516, April, 1997. 相似文献
999.
Processing-induced residual strains in solid cylinders of Nickel 200 were investigated using phase shifting moiré interferometry. Two different experimental approaches were used to study the strains produced during Tungsten-inert gas spot welding. A comparison of results for a ‘hot/fast’ and a ‘cool/slow’ weld demonstrate the capabilities of the general approach. Both experimental methods revealed distinct differences in the residual displacement and strain fields between the two types of welds. 相似文献
1000.
A. Debussche 《Journal de Mathématiques Pures et Appliquées》1998,77(10):967-988
The notion of random attractor for a dissipative stochastic dynamical system has recently been introduced. It generalizes the concept of global attractor in the deterministic theory. It has been shown that many stochastic dynamical systems associated to a dissipative partial differential equation perturbed by noise do possess a random attractor. In this paper, we prove that, as in the case of the deterministic attractor, the Hausdorff dimension of the random attractor can be estimated by using global Lyapunov exponents. The result is obtained under very natural assumptions. As an application, we consider a stochastic reaction-diffusion equation and show that its random attractor has finite Hausdorff dimension. 相似文献