全文获取类型
收费全文 | 180031篇 |
免费 | 791篇 |
国内免费 | 264篇 |
专业分类
化学 | 89882篇 |
晶体学 | 2641篇 |
力学 | 9383篇 |
综合类 | 7篇 |
数学 | 20973篇 |
物理学 | 58200篇 |
出版年
2020年 | 1852篇 |
2019年 | 2292篇 |
2018年 | 3399篇 |
2017年 | 3532篇 |
2016年 | 4168篇 |
2015年 | 1863篇 |
2014年 | 3600篇 |
2013年 | 7071篇 |
2012年 | 5550篇 |
2011年 | 6600篇 |
2010年 | 5525篇 |
2009年 | 5642篇 |
2008年 | 6375篇 |
2007年 | 6333篇 |
2006年 | 5627篇 |
2005年 | 4993篇 |
2004年 | 4831篇 |
2003年 | 4377篇 |
2002年 | 4533篇 |
2001年 | 5005篇 |
2000年 | 3697篇 |
1999年 | 2837篇 |
1998年 | 2610篇 |
1997年 | 2461篇 |
1996年 | 2256篇 |
1995年 | 2057篇 |
1994年 | 2008篇 |
1993年 | 2044篇 |
1992年 | 2077篇 |
1991年 | 2387篇 |
1990年 | 2324篇 |
1989年 | 2391篇 |
1988年 | 2269篇 |
1987年 | 2301篇 |
1986年 | 2128篇 |
1985年 | 2660篇 |
1984年 | 2674篇 |
1983年 | 2324篇 |
1982年 | 2372篇 |
1981年 | 2278篇 |
1980年 | 2080篇 |
1979年 | 2395篇 |
1978年 | 2548篇 |
1977年 | 2639篇 |
1976年 | 2729篇 |
1975年 | 2538篇 |
1974年 | 2468篇 |
1973年 | 2636篇 |
1972年 | 2153篇 |
1971年 | 1977篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
961.
D. A. Ténné V. A. Gaisler N. T. Moshegov A. I. Toropov A. P. Shebanin 《JETP Letters》1998,68(1):53-58
Experiments on Raman scattering in the “forward” geometry, permitting observation of anisotropy of the optical phonons, are
performed on specially prepared short-period GaAs/AlAs superlattice structures with the substrates removed and the surfaces
covered with an antireflective layer. The experimental data agree well with the computational results obtained for the angular
dispersion of optical phonons in superlattices on the basis of a modified continuum model.
Pis’ma Zh. éksp. Teor. Fiz. 68, No. 1, 50–55 (10 July 1998) 相似文献
962.
A new scheme is presented for the physical processes leading to the nuclear fusion reaction d(3He, 4He)p catalyzed by a negatively charged muon μ−. It is shown that the observable rate and yield of the nuclear reaction depend on a chain of ion-molecular reactions involving
the participation of the dμ 3He molecule. New calculations of the nuclear fusion rates in the dμ3He molecule are presented.
Pis’ma Zh. éksp. Teor. Fiz. 67, No. 2, 89–94 (25 January 1998)
Published in English in the original Russian journal. Edited by Steve Torstveit. 相似文献
963.
We use integrals of Cauchy type and the complex potentials of S. G. Lekhnitskii to solve the problem of the stress-strain
state of a piecewise-homogeneous anisotropic rock during the working of a horizontal seam of mineral. We study the stress
distribution in the deloaded zones. Three figures, 1 table. Bibliography: 4 titles.
Translated fromTeoreticheskaya i Prikladnaya Mekhanika, No. 27, 1997, pp. 81–86. 相似文献
964.
The Zubarev nonequilibrium statistical operator is used to describe the generalized hydrodynamic state of a magnetic fluid
in an external magnetic field. The magnetic fluid is modeled with “liquid-state” and “magnetic” subsystems described using
the classical and quantum statistics methods respectively. Equations of the generalized statistical hydrodynamics for a magnetic
fluid in a nonhomogeneous external magnetic field with the Heisenberg spin interaction are derived for “liquid-state” and
“magnetic” subsystems characterized by different nonequilibrium temperatures. These equations can be used to describe both
the weakly and strongly nonequilibrium states. Some limiting cases are analyzed in which the variables of one of the subsystems
can be formally neglected.
Translated from Teoreticheskaya i Matematicheskaya Fizika. Vol. 115, No. 1, pp. 132–153, April, 1998. 相似文献
965.
The study of the distribution of thermal fields and the thermal stresses they generate, and the influence of these factors
on the strength of piecewise-homogeneous bodies was begun and developed in the work of Ya. S. Pidstrigach, Yu. M. Kolyano,
and their students [5, 12, 13]. In the present paper we use the theory of generalized functions to reduce the two-dimensional
quasistatic problem of thermal stresses for piecewisehomogeneous bodies to solving systems of integral equations. The kernels
of these equations are chosen as the corresponding Green's functions. We obtain a single system of integral equations for
the entire region under consideration. To solve the system we apply the method of boundary elements [2]. On the basis of the
results obtained we carry out a study of the thermostressed state of a half-plane with rectangular inclusions.
Translated fromMatematichni Metodi i Fiziko-mekhnichni Polya, Vol. 40, No. 1, 1997, pp. 53–58. 相似文献
966.
V. P. Maiboroda I. E. Troyanovskii I. I. Safarov M. G. Vazagashvili I. V. Katalymova 《Journal of Mathematical Sciences》1992,60(2):1379-1382
This article examines the propagation of viscoelastic (elastic) waves in a medium consisting of two layers of finite thickness. It is found that there is a mechanical effect manifest in the monotonic dependence of the damping factor on the parameters of the system. These dependences have distinct maxima and minima, thus making it possible to optimize the damping properties of systems by varying their geometric parameters.Translated from Dinamicheskie, Sistemy, No. 4, pp. 57–62, 1985. 相似文献
967.
M. D. Bavizhev V. L. Burlikov V. I. Simanchuk A. V. Kargapol'tsev 《Russian Physics Journal》1991,34(8):727-730
Experimental data on the generation of acoustic radiation in solid targets by pulsed high-energy proton beams are outlined. The features of ultrasound generation in solids by beams of heavy charged particles are analyzed, and the possibility of using the acoustic effect of heavy charged particles to investigate the interaction between radiation and condensed media and to determine particle energies is shown.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 8, pp. 95–99, August, 1991. 相似文献
968.
R. Klein R. Grieser L. Hoog G. Huber I. Klaft P. Merz T. Kühl S. Schröder M. Grieser D. Habs W. Petrich D. Schwalm 《Zeitschrift für Physik A Hadrons and Nuclei》1992,342(4):455-461
We have performed for the first time precision spectroscopy on a coasting fast7Li+ ion beam in a storage ring. The ion beam moving with 6.4% speed of light was first electron cooled and then merged with two counterpropagating laser beams acting on two different hyperfine transitions sharing a common upper level (λ-system). One laser was frequency locked to thea 3 127J2 hfs frequency component established as a secondary frequency standard at 514 nm. The second laser was tuned over theλ-resonance, which was recorded relative to127J2 hfs components. This experiment is sensitive to the time dilation in fast moving frames and will lead to new limits for the verification of special relatively. The present status of the experiment and perspectives in accuracy are discussed. 相似文献
969.
The stable quasistationary mixing of ternary gas mixtures in a system of two chambers connected by a capillary is described
by a theoretical model which predicts the density distribution of the mixture along the length of the diffusion channel. It
is demonstrated that inversion of the density gradient can occur due to a nonlinear concentration distribution of the heavy
component in a diffusion “gate” effect. The results obtained using this model are compared with the experimental data.
Zh. Tekh. Fiz. 68, 14–17 (May 1998) 相似文献
970.
The possibility of the existence of a magnetostatic analog of Love surface elastic waves is predicted. They appear in situations
where the conditions for the existence of magnetostatic volume waves hold in the upper layer of a ferromagnetic bilayer, but
not in the lower layer.
Zh. Tekh. Fiz. 68, 85–90 (October 1998) 相似文献