首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   1308026篇
  免费   29897篇
  国内免费   12171篇
化学   648223篇
晶体学   20519篇
力学   75398篇
综合类   419篇
数学   241090篇
物理学   364445篇
  2021年   14619篇
  2020年   16972篇
  2019年   17218篇
  2018年   12789篇
  2016年   28512篇
  2015年   21868篇
  2014年   31792篇
  2013年   76162篇
  2012年   37070篇
  2011年   31832篇
  2010年   37177篇
  2009年   40101篇
  2008年   31317篇
  2007年   26222篇
  2006年   33202篇
  2005年   25344篇
  2004年   27242篇
  2003年   26156篇
  2002年   27569篇
  2001年   24966篇
  2000年   22807篇
  1999年   21916篇
  1998年   21102篇
  1997年   20984篇
  1996年   21328篇
  1995年   19394篇
  1994年   18804篇
  1993年   18283篇
  1992年   17749篇
  1991年   18057篇
  1990年   17270篇
  1989年   17307篇
  1988年   16812篇
  1987年   16851篇
  1986年   15728篇
  1985年   22172篇
  1984年   23533篇
  1983年   19798篇
  1982年   21521篇
  1981年   20759篇
  1980年   20099篇
  1979年   20091篇
  1978年   21513篇
  1977年   21059篇
  1976年   20717篇
  1975年   19380篇
  1974年   19014篇
  1973年   19496篇
  1972年   14016篇
  1967年   12270篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
941.
Physics of the Solid State - It is shown theoretically that a deformed crystal exhibiting structural instability can be treated as a quantum system of pseudospins. The quantum behavior of atoms...  相似文献   
942.
943.
944.
Three types of transparency of a semiconductor superlattice, namely, self-induced, induced, and selective transparency, were studied. The conditions of their existence and the causes of their destruction were revealed. It was shown that the state of self-induced transparency, which is unstable in a harmonic field, can be stable in a biharmonic field.  相似文献   
945.
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   
946.
Magnetoplasma waves and inhomogeneous (complex) waves in an infinite semiconductor superlattice in a magnetic field are studied, and dispersion curves are obtained. It is shown analytically and numerically that, in periodic structures, among inhomogeneous waves, there are many complex waves for which the imaginary part of the wave vector is greater than the real part. The effect of dissipation in a medium on the dispersion curves of magnetoplasma waves is examined. The dependence of the minimum phase velocity on the collision frequency and the magnetic field strength is studied.  相似文献   
947.
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   
948.
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   
949.
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   
950.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号