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   1320019篇
  免费   25730篇
  国内免费   7745篇
化学   654716篇
晶体学   20314篇
力学   74220篇
综合类   103篇
数学   239732篇
物理学   364409篇
  2021年   13466篇
  2020年   15869篇
  2019年   16009篇
  2018年   12685篇
  2016年   27656篇
  2015年   20688篇
  2014年   30266篇
  2013年   74059篇
  2012年   36622篇
  2011年   32857篇
  2010年   36623篇
  2009年   39116篇
  2008年   32728篇
  2007年   28262篇
  2006年   34478篇
  2005年   27207篇
  2004年   28439篇
  2003年   27114篇
  2002年   28292篇
  2001年   26572篇
  2000年   23777篇
  1999年   22027篇
  1998年   20781篇
  1997年   20797篇
  1996年   20990篇
  1995年   19075篇
  1994年   18500篇
  1993年   18061篇
  1992年   17813篇
  1991年   18150篇
  1990年   17381篇
  1989年   17414篇
  1988年   17008篇
  1987年   17021篇
  1986年   15922篇
  1985年   22365篇
  1984年   23668篇
  1983年   19875篇
  1982年   21579篇
  1981年   20821篇
  1980年   20172篇
  1979年   20287篇
  1978年   21614篇
  1977年   21204篇
  1976年   20899篇
  1975年   19634篇
  1974年   19237篇
  1973年   19765篇
  1972年   14257篇
  1967年   12488篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
931.
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   
932.
933.
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   
934.
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   
935.
936.
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   
937.
938.
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   
939.
940.
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