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   236891篇
  免费   2672篇
  国内免费   1184篇
化学   109326篇
晶体学   3673篇
力学   12523篇
综合类   46篇
数学   37793篇
物理学   77386篇
  2018年   10336篇
  2017年   11226篇
  2016年   5896篇
  2015年   2219篇
  2014年   1797篇
  2013年   5394篇
  2012年   8543篇
  2011年   18287篇
  2010年   10836篇
  2009年   10720篇
  2008年   15683篇
  2007年   19512篇
  2006年   4584篇
  2005年   11718篇
  2004年   7459篇
  2003年   6958篇
  2002年   4767篇
  2001年   3910篇
  2000年   3155篇
  1999年   2408篇
  1998年   2055篇
  1997年   2015篇
  1996年   2126篇
  1995年   1982篇
  1994年   1749篇
  1993年   1722篇
  1992年   1919篇
  1991年   1899篇
  1990年   1814篇
  1989年   1837篇
  1988年   1826篇
  1987年   1806篇
  1986年   1702篇
  1985年   2260篇
  1984年   2381篇
  1983年   1997篇
  1982年   2309篇
  1981年   2125篇
  1980年   2166篇
  1979年   2169篇
  1978年   2297篇
  1977年   2123篇
  1976年   2186篇
  1975年   2104篇
  1974年   1947篇
  1973年   2197篇
  1972年   1322篇
  1971年   1001篇
  1968年   1152篇
  1967年   1132篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
921.
A realization of graphs with vertices of bounded branching in a subspace of bounded depth is considered. A volume order inside of which an arbitrary graph can be realized is determined.  相似文献   
922.
We study the generalization of the Willmore functional for surfaces in the three-dimensional Heisenberg group. Its construction is based on the spectral theory of the Dirac operator entering into theWeierstrass representation of surfaces in this group. Using the surfaces of revolution we demonstrate that the generalization resembles the Willmore functional for the surfaces in the Euclidean space in many geometrical aspects. We also observe the relation of these functionals to the isoperimetric problem.  相似文献   
923.
Based on the Lenard relations, we completely classify integrable deformations of general algebraic curves. We construct the general solution of the Lenard relation from the invariance condition with respect to an element of the Galois group of the curve. We give some examples and also some associated conservation laws. __________ Translated from Teoreticheskaya i Matematicheskaya Fizika, Vol. 151, No. 3, pp. 458–469, June, 2007.  相似文献   
924.
925.
926.
A mathematical model of the system composed of two sensors, the semicircular canal and the sacculus, is suggested. The model is described by three lines of blocks, each line of which has the following structure: a biomechanical block, a mechanoelectrical transduction mechanism, and a block describing the hair cell ionic currents and membrane potential dynamics. The response of this system to various stimuli (head rotation under gravity and falling) is investigated. Identification of the model parameters was done with the experimental data obtained for the axolotl (Ambystoma tigrinum) at the Institute of Physiology, Autonomous University of Puebla, Mexico. Comparative analysis of the semicircular canal and sacculus membrane potentials is presented. __________ Translated from Fundamentalnaya i Prikladnaya Matematika, Vol. 11, No. 7, pp. 207–220, 2005.  相似文献   
927.
A scale-free test for exponentiality is proposed which is consistent within an extended set of models, including, but not limited to, the “renewal new better than used in expectation” (RNBUE) class of life distributions. The limiting null distribution of the test statistics is derived, and the approximate local Bahadur efficiency is calculated for several families of alternatives. Finite-sample properties of the proposed procedures are investigated via simulation. Bibliography: 24 titles. __________ Translated from Zapiski Nauchnykh Seminarov POMI, Vol. 339, 2006, pp. 63–77.  相似文献   
928.
929.
The polarition linewidth is calculated as a function of magnetic field applied perpendicular to the microcavity plane for microcavity excition-polaritons scattered by free electrons in a quantum well. The calculated function exhibits oscillatory behavior; i.e., the scattering rate either increases or decreases with magnetic induction. Possible applications of this effect are discussed.  相似文献   
930.
Single-particle matrix elements of nucleon transfer were calculated by the Woods-Saxon potential wave functions. The results are compared with the ones calculated by the spherical-well approximation. The eligibility of the approximation of the mean field of nuclei by the spherical well to study the initial stage of nuclear reactions at heavy-ion collisions is demonstrated. The text was submitted by the authors in English.  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