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   8085篇
  免费   569篇
  国内免费   756篇
化学   146篇
晶体学   1篇
力学   342篇
综合类   115篇
数学   7906篇
物理学   900篇
  2023年   91篇
  2022年   89篇
  2021年   106篇
  2020年   182篇
  2019年   199篇
  2018年   176篇
  2017年   222篇
  2016年   205篇
  2015年   184篇
  2014年   367篇
  2013年   656篇
  2012年   304篇
  2011年   425篇
  2010年   393篇
  2009年   483篇
  2008年   591篇
  2007年   593篇
  2006年   503篇
  2005年   493篇
  2004年   374篇
  2003年   386篇
  2002年   300篇
  2001年   275篇
  2000年   226篇
  1999年   237篇
  1998年   217篇
  1997年   212篇
  1996年   138篇
  1995年   91篇
  1994年   76篇
  1993年   63篇
  1992年   55篇
  1991年   57篇
  1990年   33篇
  1989年   33篇
  1988年   35篇
  1987年   22篇
  1986年   28篇
  1985年   47篇
  1984年   35篇
  1983年   20篇
  1982年   26篇
  1981年   32篇
  1980年   19篇
  1979年   27篇
  1978年   24篇
  1977年   18篇
  1976年   16篇
  1974年   8篇
  1973年   6篇
排序方式: 共有9410条查询结果,搜索用时 93 毫秒
991.
By using probabilistic approaches, Liouville theorems are proved for a class of Riemannian manifolds with Ricci curvatures bounded below by a negative function. Indeed, for these manifolds we prove that all harmonic functions (maps) with certain growth are constant. In particular, the well-known Liouville theorem due to Cheng for sublinear harmonic functions (maps) is generalized. Moreover, our results imply the Brownian coupling property for a class of negatively curved Riemannian manifolds. This leads to a negative answer to a question of Kendall concerning the Brownian coupling property.  相似文献   
992.
We consider some Sobolev-type spaces and obtain a necessary and sufficient condition for their embedding in a Lebesgue space.  相似文献   
993.
We establish, for various scenarios, whether or not interruptible exact stationary sampling is possible when a finite-state Markov chain can only be viewed passively. In particular, we prove that such sampling is not possible using a single copy of the chain. Such sampling is possible when enough copies of the chain are available, and we provide an algorithm that terminates with probability one.  相似文献   
994.
该文给出了Logistic分布纪录值序列部分和的中心极限定理;对于Pareto分布纪录值序列的部分和T_n,获得了lnT_n的中心极限定理.这一工作不仅具有概率论的极限理论方面的研究价值,而且在金融、保险等领域也具有相当重要的应用前景.  相似文献   
995.
Below, we briefly report on the progress in the development of the Filter Diagonalization technique when filtering is carried out with the aid of Finite Fourier Transform (FFT) eigenfunctions. During recent years interest in these functions, also known as ‘prolates’, or ‘slepians’, has increased among scientists doing research in the field of signal processing. The main explanation to this follows from the set of very special extremal and orthogonality properties exibited by the FFT eigenfunctions. Recent results of Walter and Shen on sampling with prolate spheroidal functions will necessary produce a new wave of interest. In the presented, Filter diagonalization machinery, we show that the sampling formula of Walter and Shen simplifies essentially the computation of matrix elements as certain 2D–integrals involving FFT eigenfunctions.  相似文献   
996.
LetN be a sufficiently large even integer and
  相似文献   
997.
Summary The virial theorem for a molecule in the relativistic clamped-nuclei approximation is derived. The individual energy contributionsA (momentum energy),B (mass energy),T=A+B (kinetic energy) andV (potential energy) are expressed in terms ofE, E/R (derivate w.r.t. the nuclear coordinates) and the relativistic correction E/2 (derivative w.r.t. Sommerfield's fine-structure constant ). IfE and E/R are known as functions of , then all individual energy terms are also known as functions of . As an example, numerical results for H 2 + are presented. The relativistic and nonrelativistic potential energy curves and the paradoxical behavior of their different contributions are analyzed and interpreted in both the largeR and shortR ranges.Dedicated to Professor W. Kutzelnigg on the occasion of his 60th birthday  相似文献   
998.
999.
We prove theH-stability property and the existence of the thermodynamic limit of the free energy density of the two-dimensional, one-component classical plasma. We give lower and upper bounds on the free energy density in any dimensionv and draw some consequences.  相似文献   
1000.
A diatomic molecule modeled by a Morse oscillator is shown to undergo dissociation if the external electric field, in which the molecule is placed, undergoes discontinuous reversals. A threshold frequency of reversal is found to exist. The classical behavior is compared with its quantum counterpart. The mechanism of dissociation is analyzed. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2008  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