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   1318772篇
  免费   25795篇
  国内免费   7701篇
化学   654499篇
晶体学   20172篇
力学   74134篇
综合类   107篇
数学   239678篇
物理学   363678篇
  2021年   13522篇
  2020年   15927篇
  2019年   16054篇
  2016年   27555篇
  2015年   20682篇
  2014年   30428篇
  2013年   74263篇
  2012年   36495篇
  2011年   32176篇
  2010年   36108篇
  2009年   38730篇
  2008年   31889篇
  2007年   27130篇
  2006年   34279篇
  2005年   26162篇
  2004年   28015篇
  2003年   26889篇
  2002年   28129篇
  2001年   27448篇
  2000年   24147篇
  1999年   22166篇
  1998年   20861篇
  1997年   20870篇
  1996年   21062篇
  1995年   19165篇
  1994年   18625篇
  1993年   18119篇
  1992年   18146篇
  1991年   18415篇
  1990年   17670篇
  1989年   17716篇
  1988年   17312篇
  1987年   17303篇
  1986年   16195篇
  1985年   22587篇
  1984年   23859篇
  1983年   20002篇
  1982年   21664篇
  1981年   20904篇
  1980年   20236篇
  1979年   20457篇
  1978年   21733篇
  1977年   21387篇
  1976年   21014篇
  1975年   19702篇
  1974年   19301篇
  1973年   19748篇
  1972年   14257篇
  1968年   12132篇
  1967年   12529篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
921.
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   
922.
923.
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   
924.
A method of teaching of one of the divisions of electrodynamics devoted to relativity theory is suggested. The presentation is based on the four-dimensional formalism, which allows a number of fundamental physical phenomena to be considered from a unified position. The content is in full conformity with the approved standard programs for students and postgraduates of radio physical and radio technical specialities of universities. The methods can be useful to the teachers, scientific workers, and engineers concerned with other directions and specialities.  相似文献   
925.
926.
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   
927.
928.
A physical multidimensional local model of the propagation process of a laser pulse in air having no analogy to famous models in laser physics is constructed. It is based on the representations of classical wave mechanics characteristic of the theory of scalar wave fields.  相似文献   
929.
930.
The study of the effect of a perfectly conducting plane placed at a certain distance from the surface of a potassium niobate crystal on the characteristics of the generalized Rayleigh and Gulyaev-Bleustein surface waves is continued. In addition, the effect of an infinitely thin conducting layer applied to the surface of the piezoelectric on the characteristics of these waves is analyzed. It is found that a variation in the conductance of this layer can produce a result that completely differs from the result obtained when a perfectly conducting plane is moved toward the surface, although the extreme states of these actions (electrically open and short-circuited surfaces) are identical. A possible physical explanation of this difference is proposed.  相似文献   
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