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   188779篇
  免费   2837篇
  国内免费   523篇
化学   101435篇
晶体学   2227篇
力学   7666篇
综合类   12篇
数学   21738篇
物理学   59061篇
  2020年   1596篇
  2019年   1543篇
  2018年   1975篇
  2017年   1942篇
  2016年   3468篇
  2015年   2318篇
  2014年   3314篇
  2013年   8108篇
  2012年   6594篇
  2011年   8083篇
  2010年   5518篇
  2009年   5302篇
  2008年   7366篇
  2007年   7343篇
  2006年   6897篇
  2005年   6330篇
  2004年   5564篇
  2003年   4793篇
  2002年   4704篇
  2001年   5067篇
  2000年   3932篇
  1999年   3014篇
  1998年   2628篇
  1997年   2573篇
  1996年   2447篇
  1995年   2337篇
  1994年   2357篇
  1993年   2191篇
  1992年   2511篇
  1991年   2452篇
  1990年   2270篇
  1989年   2249篇
  1988年   2162篇
  1987年   2073篇
  1986年   1970篇
  1985年   2654篇
  1984年   2749篇
  1983年   2272篇
  1982年   2459篇
  1981年   2338篇
  1980年   2296篇
  1979年   2408篇
  1978年   2551篇
  1977年   2431篇
  1976年   2430篇
  1975年   2346篇
  1974年   2384篇
  1973年   2324篇
  1972年   1496篇
  1971年   1366篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
71.
72.
On Quantum Team Games   总被引:2,自引:0,他引:2  
Recently Liu and Simaan (2004) convex static multi-team classical games have been introduced. Here they are generalized to both nonconvex, dynamic and quantum games. Puu's incomplete information dynamical systems are modified and applied to Cournot team game. The replicator dynamics of the quantum prisoner's dilemma game is also studied.  相似文献   
73.
The influence of processing parameters on the electrical characteristics of RuO2/LaAlO3/Si metal-oxide-semiconductor structures was investigated. In particular, the sputtering regime during deposition of LaAlO3 on Si and the atmosphere used in the post-deposition annealing step were addressed by determining capacitance-voltage and gate current-voltage characteristics. These results were correlated with compositional information obtained by Rutherford backscattering spectrometry and nuclear reaction analysis. A post-deposition annealing step in oxygen at 600 °C resulted in better electrical characteristics of the final structure as compared to the same treatment performed in nitrogen. This result is explained by oxygen ability to heal oxygen vacancies in the LaAlO3 film, especially at the dielectric/semiconductor interface region. A thermalized sputtering regime during deposition of LaAlO3 on Si leads to capacitors with electrical characteristics superior to those deposited in ballistic regime. PACS 77.84.Dy; 81.15.Cd; 81.40.Gh; 73.40.Qv; 82.80.Yc  相似文献   
74.
75.
We consider Ising-spin systems starting from an initial Gibbs measure ν and evolving under a spin-flip dynamics towards a reversible Gibbs measure μ≠ν. Both ν and μ are assumed to have a translation-invariant finite-range interaction. We study the Gibbsian character of the measure νS(t) at time t and show the following: (1) For all ν and μ, νS(t) is Gibbs for small t. (2) If both ν and μ have a high or infinite temperature, then νS(t) is Gibbs for all t > 0. (3) If ν has a low non-zero temperature and a zero magnetic field and μ has a high or infinite temperature, then νS(t) is Gibbs for small t and non-Gibbs for large t. (4) If ν has a low non-zero temperature and a non-zero magnetic field and μ has a high or infinite temperature, then νS(t) is Gibbs for small t, non-Gibbs for intermediate t, and Gibbs for large t. The regime where μ has a low or zero temperature and t is not small remains open. This regime presumably allows for many different scenarios. Received: 26 April 2001 / Accepted: 10 October 2001  相似文献   
76.
Algebraic methods in quantum mechanics: from molecules to polymers   总被引:2,自引:0,他引:2  
We present a brief review of algebraic techniques developed and applied in molecular spectroscopy in the last five years. We also outline perspectives for new applications of the Lie algebraic method in the first decade of the new century. Received 21 November 2001  相似文献   
77.
Diffraction by a semitransparent screen is considered in the framework of the nonlinear Schrödinger equation. The case of a defocusing medium is investigated. The method used represents a synthesis of the method of Riemann's matrix problem and the technique of Whitham's deformations of spectral curves.Translated from Zapiski Nauchnykh Seminarov Leningradskogo Otdeleniya Matematicheskogo Instituta im. V. A. Steklova, Vol. 179, pp. 23–31, 1989.  相似文献   
78.
Under idealized conditions, electroconvection in a nematic liquid crystal sets in at a well-defined threshold of the driving ac voltage. Fluctuating convection rolls of a small amplitude below that threshold have been observed recently. The measurement of the amplitude of these fluctuations is described in detail in this paper. It is based on averaging the light intensity signals using the structure function and a quantitative analysis of the light deflection.  相似文献   
79.
80.
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