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   1392922篇
  免费   25712篇
  国内免费   7761篇
化学   696193篇
晶体学   20904篇
力学   76151篇
综合类   113篇
数学   246125篇
物理学   386909篇
  2021年   13533篇
  2020年   15920篇
  2019年   16034篇
  2018年   15836篇
  2017年   14489篇
  2016年   29203篇
  2015年   21039篇
  2014年   30366篇
  2013年   74218篇
  2012年   40731篇
  2011年   40745篇
  2010年   39686篇
  2009年   41671篇
  2008年   39249篇
  2007年   36017篇
  2006年   38170篇
  2005年   33170篇
  2004年   32943篇
  2003年   30388篇
  2002年   30702篇
  2001年   29704篇
  2000年   25486篇
  1999年   22868篇
  1998年   21152篇
  1997年   21069篇
  1996年   21160篇
  1995年   19175篇
  1994年   18642篇
  1993年   18188篇
  1992年   18229篇
  1991年   18495篇
  1990年   17696篇
  1989年   17770篇
  1988年   17395篇
  1987年   17303篇
  1986年   16208篇
  1985年   22614篇
  1984年   23859篇
  1983年   20054篇
  1982年   21660篇
  1981年   20895篇
  1980年   20221篇
  1979年   20467篇
  1978年   21755篇
  1977年   21363篇
  1976年   21059篇
  1975年   19771篇
  1974年   19434篇
  1973年   19905篇
  1972年   14395篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
901.
In the present paper it is shown that if S1 and S2 are two Clifford topological semigroups satisfying certain conditions and T is an isometric isomorphism of LUC(S1*) onto LUC(S2*), then T maps S1 topologically isomorphically onto S2. Furthermore, T maps M l n(S1) (M(S1), respectively) isometrically isomorphically onto M l n(S2) (M(S2), respectively). Indeed, we have obtained a generalization of a well-known result of Ghahramani, Lau and Losert for locally compact groups to a more general setting of Clifford topological semigroups.  相似文献   
902.
We obtain expressions for the energy spectrum widths of Rayleigh waves corresponding to their deformational coupling to Fermi and Boltzmann electrons in a two-dimensional layer near the surface of a semibounded solid. We evaluate the nonequilibrium energy of Rayleigh waves that depends on these widths and is caused by the same coupling to the corresponding hot electrons. We show that this energy is independent of the degeneracy degree of the electrons and is given by the mean energy of free Rayleigh waves heated up to temperature of the electrons. We find conditions under which the thermodynamics is determined by this nonequilibrium energy of Rayleigh waves in films of a certain thickness with Fermi electrons near the surface and by the equilibrium energy of bulk phonons in thicker samples. All the results are obtained using the Keldysh diagram technique applied to the case of semibounded media.  相似文献   
903.
We propose a unified method for deducing recursive relations for the canonical partition function of a system of noninteracting particles with charge conservation if the particles follow the Bose–Einstein, Fermi–Dirac, or Maxwell–Boltzmann statistics or parastatistics. For all these types of statistics, we find recursive relations for the partition function of a new statistical model of nuclear multifragmentation with electric charge and baryon number conservation, accounting for the internal degrees of freedom of the nuclear fragments.  相似文献   
904.
We establish a relation between stable distributions in probability theory and the fractional integral. Moreover, it turns out that the parameter of the stable distribution coincides with the exponent of the fractional integral. It follows from an analysis of the obtained results that equations with the fractional time derivative describe the evolution of some physical system whose time degree of freedom becomes stochastic, i.e., presents a sum of random time intervals subject to a stable probability distribution. We discuss relations between the fractal Cantor set (Cantor strips) and the fractional integral. We show that the possibility to use this relation as an approximation of the fractional integral is rather limited.  相似文献   
905.
The European Physical Journal C - The design constraints and the target physics performance of the ATLAS Electromagnetic Calorimeter are reviewed, and the construction status is summarized....  相似文献   
906.
907.
Applied Magnetic Resonance - We examined by electron spin resonance (ESR) spectroscopy the thermal decay of radicals as induced by γ-irradiation on pepper. Upon irradiation, the satellite...  相似文献   
908.
A nonlinear (in the cubic approximation) relaxation equation of state is derived for a rod containing cracks partially filled with an incompressible viscous liquid. The nonlinear effects of the self-action and interaction of low-and high-frequency longitudinal elastic waves propagating in such a rod are studied for the cases of identical and size-varied cracks. Linear and nonlinear acoustic parameters characterizing the self-action and interaction of elastic waves in a cracked rod are determined.  相似文献   
909.
910.
We describe in detail fundamental properties of continuity modules of various orders in the spaces L p of functions defined on a finite segment. We establish some general estimates of seminorms in terms of continuity modules with the best known constants. An example of application of these results to the best approximations is considered. Bibliography: 32 titles.  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