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   1295篇
  免费   62篇
  国内免费   96篇
化学   203篇
力学   81篇
综合类   14篇
数学   877篇
物理学   278篇
  2023年   14篇
  2022年   8篇
  2021年   14篇
  2020年   24篇
  2019年   36篇
  2018年   45篇
  2017年   43篇
  2016年   37篇
  2015年   28篇
  2014年   44篇
  2013年   102篇
  2012年   41篇
  2011年   54篇
  2010年   60篇
  2009年   61篇
  2008年   82篇
  2007年   83篇
  2006年   72篇
  2005年   69篇
  2004年   63篇
  2003年   60篇
  2002年   64篇
  2001年   48篇
  2000年   44篇
  1999年   38篇
  1998年   23篇
  1997年   33篇
  1996年   13篇
  1995年   11篇
  1994年   19篇
  1993年   13篇
  1992年   14篇
  1991年   10篇
  1990年   5篇
  1989年   3篇
  1988年   8篇
  1987年   4篇
  1986年   9篇
  1985年   5篇
  1984年   3篇
  1983年   4篇
  1982年   6篇
  1981年   3篇
  1980年   6篇
  1979年   4篇
  1977年   5篇
  1976年   6篇
  1975年   4篇
  1974年   4篇
  1969年   3篇
排序方式: 共有1453条查询结果,搜索用时 15 毫秒
21.
赵益坤  节存来  王磊 《大学数学》2007,23(1):166-169
讨论了第一类曲线积分中值定理“中间点”的渐近性质,得到了更具一般性的新结果.  相似文献   
22.
We consider an extension of the Feynman path integral to the quantum mechanics of noncommuting spatial coordinates and formulate the corresponding formalism for noncommutative classical dynamics related to quadratic Lagrangians (Hamiltonians). The basis of our approach is that a quantum mechanical system with a noncommutative configuration space can be regarded as another effective system with commuting spatial coordinates. Because the path integral for quadratic Lagrangians is exactly solvable and a general formula for the probability amplitude exists, we restrict our research to this class of Lagrangians. We find a general relation between quadratic Lagrangians in their commutative and noncommutative regimes and present the corresponding noncommutative path integral. This method is illustrated with two quantum mechanical systems in the noncommutative plane: a particle in a constant field and a harmonic oscillator.  相似文献   
23.
We first state a uniform convergence theorem for finite-part integrals which are derivatives of weighted Cauchy principal value integrals. We then give a two-stage process to modify approximating splines and optimal nodal splines in such a way that the conditions of this theorem are satisfied. Consequently, these modified splines can be used in the numerical evaluation of these finite-part integrals.  相似文献   
24.
In this paper cubature formulas based on bivariate C 1 local polynomial splines with a four directional mesh [4] are generated and studied. Some numerical results with comparison with other methods are given. Moreover the method proposed is applied to the numerical evaluation of 2‐D singular integrals defined in the Hadamard finite part sense. Computational features, convergence properties and error bounds are proved. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   
25.
We give a short proof of the inner product conjecture for the symmetric Macdonald polynomials of type An-1. As a special case, the corresponding constant term conjecture is also proved.  相似文献   
26.
The Kurzweil-Henstock integral formalism is applied to establish the existence of solutions to the linear integral equations of Volterra-typewhere the functions are Banach-space valued. Special theorems on existence of solutions concerning the Lebesgu3 integral setting are obtained. These sharpen earlier results.  相似文献   
27.
We derive explicit isomorphism formulas between weighted Dirichlet integrals for harmonic functions and boundary Dirichlet forms. Applications yield results on traces of Markov processes and convergence quasieverywhere of harmonic functions.  相似文献   
28.
含余割核奇异积分修改的反演问题   总被引:1,自引:0,他引:1  
针对含余害核奇异积分反演问题在指κ<0时一般无解的情况,本文提出并求解两种修改的反演问题,而后一种修改反演问题的提法与此前类似问题颇不相同,由于运用了推广的留数定理和Bertrand型换序公式使本问题及类似问题解法得以简化。  相似文献   
29.
The calculation of two-temperature transport coefficients in an argon–hydrogen plasma at atmospheric pressure is performed using a new theory of two-temperature transport properties recently presented. The latter takes into account the coupling between electrons and heavy species, coupling neglected in the already existing theories of Devoto and Bonnefoi. Transport coefficients are calculated at two-temperatures, the kinetic temperature of electrons Te being different from that of heavy species Th. This paper is divided into two parts. The first one is related to elastic processes and its aim is to compare the results obtained with this new theory for viscosity , translational thermal conductivities tr e and tr h and electrical conductivity with the previous results of Bonnefoi. The composition is calculated with the modified equilibrium constant of van de Sanden et al. and the most recent interaction potential are discussed. As it could be expected the electron translational thermal conductivity and the electrical conductivity calculated when taking into account or not the coupling between electrons and heavy species show non-negligible discrepancies. Besides this comparison, the results also show the drastic influence of the non-equilibrium parameter =Te/Th on the values of , , tr e, and tr h.  相似文献   
30.
A systematic extension of Ruedenberg's expansion formula is applied to evaluate two-electron integrals occurring in calculations on molecular structure. Minimum STO basis sets are used for all SCF-calculations within the framework of the MEDO-method (Multipole Expansion of Diatomic Overlap). The errors due to this approximation scheme are almost negligible compared to those introduced by the truncated basis set: LiH, Li2 and N2 are chosen as examples.  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