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   29594篇
  免费   828篇
  国内免费   235篇
化学   19870篇
晶体学   130篇
力学   659篇
综合类   1篇
数学   5585篇
物理学   4412篇
  2021年   281篇
  2020年   367篇
  2019年   328篇
  2018年   285篇
  2017年   302篇
  2016年   625篇
  2015年   644篇
  2014年   676篇
  2013年   1449篇
  2012年   1441篇
  2011年   1756篇
  2010年   989篇
  2009年   838篇
  2008年   1503篇
  2007年   1523篇
  2006年   1601篇
  2005年   1432篇
  2004年   1366篇
  2003年   1134篇
  2002年   1078篇
  2001年   479篇
  2000年   435篇
  1999年   410篇
  1998年   401篇
  1997年   450篇
  1996年   423篇
  1995年   390篇
  1994年   424篇
  1993年   369篇
  1992年   344篇
  1991年   337篇
  1990年   298篇
  1989年   299篇
  1988年   278篇
  1987年   237篇
  1986年   256篇
  1985年   378篇
  1984年   388篇
  1983年   315篇
  1982年   360篇
  1981年   336篇
  1980年   351篇
  1979年   286篇
  1978年   322篇
  1977年   300篇
  1976年   236篇
  1975年   205篇
  1974年   212篇
  1973年   173篇
  1972年   121篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
81.
82.
83.
Preface     
This issue of Journal of Thermal Analysis and Calorimetry contains selected papers based on presentations in the field of thermal characteristics of advanced polymer systems presented at the 8th International Symposium on Polymers for Advanced Technologies (PAT 2005) held in Budapest, September 2005. Guest Editors  相似文献   
84.
In this paper, the possibility of using the gradients of the temperature and of the internal parameters as additional state variables in Continuum Thermodynamics is considered. The expressions of the two principles are discussed and Clausius–Duhem inequality is derived under an appropriate statement of the internal entropy production. Several formulations are proposed and compared to existing results in the literature. To cite this article: P. Ireman, Q.S. Nguyen, C. R. Mecanique 332 (2004).  相似文献   
85.
86.
A new parallel storm surge model, the Parallel Environmental Model (PEM), is developed and tested by comparisons with analytic solutions. The PEM is a 2‐D vertically averaged, wetting and drying numerical model and can be operated in explicit, semi‐implicit and fully implicit modes. In the implicit mode, the propagation, Coriolis and bottom friction terms can all be treated implicitly. The advection and diffusion terms are solved with a parallel Eulerian–Lagrangian scheme developed for this study. The model is developed specifically for use on parallel computer systems and will function accordingly in either explicit of implicit modes. Storm boundary conditions are based on a simple exponential decay of pressure from the centre of a storm. The simulated flooding caused by a major Category 5 hurricane making landfall in the Indian River Lagoon, Florida is then presented as an example application of the PEM. Copyright © 2003 John Wiley & Sons, Ltd.  相似文献   
87.
A cube factorization of the complete graph on n vertices, Kn, is a 3‐factorization of Kn in which the components of each factor are cubes. We show that there exists a cube factorization of Kn if and only if n ≡ 16 (mod 24), thus providing a new family of uniform 3‐factorizations as well as a partial solution to an open problem posed by Kotzig in 1979. © 2004 Wiley Periodicals, Inc.  相似文献   
88.
Duality principles in Gabor theory such as the Ron–Shen duality principle and the Wexler–Raz biorthogonality relations play a fundamental role for analyzing Gabor systems. In this article we present a general approach to derive duality principles in abstract frame theory. For each sequence in a separable Hilbert space we define a corresponding sequence dependent only on two orthonormal bases. Then we characterize exactly properties of the first sequence in terms of the associated one, which yields duality relations for the abstract frame setting. In the last part we apply our results to Gabor systems.  相似文献   
89.
90.
Deformation quantization is a powerful tool for quantizing theories with bosonic and fermionic degrees of freedom. The star products involved generate the mathematical structures which have recently been used in attempts to analyze the algebraic properties of quantum field theory. In the context of quantum mechanics they provide a quantization procedure for systems with either bosonic or fermionic degrees of freedom. We illustrate this procedure for a number of physical examples, including bosonic, fermionic, and supersymmetric oscillators. We show how non-relativistic and relativistic particles with spin can be naturally described in this framework.  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