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   203532篇
  免费   1291篇
  国内免费   428篇
化学   104866篇
晶体学   3396篇
力学   10312篇
综合类   10篇
数学   21915篇
物理学   64752篇
  2021年   1976篇
  2020年   2010篇
  2019年   2569篇
  2018年   3661篇
  2017年   3674篇
  2016年   4815篇
  2015年   2353篇
  2014年   4309篇
  2013年   8605篇
  2012年   6848篇
  2011年   8053篇
  2010年   6476篇
  2009年   6668篇
  2008年   7652篇
  2007年   7619篇
  2006年   6710篇
  2005年   5930篇
  2004年   5653篇
  2003年   5177篇
  2002年   5165篇
  2001年   5620篇
  2000年   4144篇
  1999年   3147篇
  1998年   2710篇
  1997年   2775篇
  1996年   2556篇
  1995年   2215篇
  1994年   2334篇
  1993年   2232篇
  1992年   2530篇
  1991年   2651篇
  1990年   2558篇
  1989年   2628篇
  1988年   2540篇
  1987年   2558篇
  1986年   2418篇
  1985年   3038篇
  1984年   3108篇
  1983年   2601篇
  1982年   2573篇
  1981年   2531篇
  1980年   2341篇
  1979年   2718篇
  1978年   2677篇
  1977年   2877篇
  1976年   2882篇
  1975年   2670篇
  1974年   2608篇
  1973年   2719篇
  1972年   2089篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
This paper is in answer to the comment on the GRG paper: Lockerbie N.A. Gen. Rel. Grav. 36, 593 (2004), made by A.V. Sanders, G.T. Gillies (ibid.). N. A. Lockerbie is a member of the STEP (Satellite Test of the Equivalence Principle) Science Study Team, and an Associate of the Institute for Gravitational Research at the University of Glasgow, Scotland, UK.  相似文献   
102.
The spectra of the intensity fluctuations of light scattered by large (erythrocytes of whole blood) and small (vesicles of surgical bile) particles in natural conditions were studied. It is shown that photon correlation spectroscopy can be used in analysis of variations in the size of biological particles in normal and pathological conditions and as an express method of noninvasive diagnostics of diseases.  相似文献   
103.
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 55, No. 4, pp. 613–618, October, 1991.  相似文献   
104.
The behavior of the edges of cuts in shallow shells with the symmetric combined action of tension and flexure is investigated. For shells of different curvature with one and two parallel or collinear cuts, the load region in which there is no contact of the cut edges in the course of shell deformation is determined.Translated from Teoreticheskaya i Prikladnaya Mekhanika, No. 19, pp. 98–100, 1988.  相似文献   
105.
Modifications are introduced into the large-particle method to make it possible to use the method in arbitrary nonrectangular computing nets in the study of the flow of an ideal compressible gas over mobile thin permeable membranes. A problem in the aeroelasticity of a parachute is stated. An example is given of the solution of a problem in the stationary formulation for an axially symmetric parachute in the wake of a cylindrical leading body for supersonic flow.Translated fromDinamicheskie Sistemy, No. 6, 1987, pp. 16–22  相似文献   
106.
107.
Results of an experimental observation of the voltage oscillations associated with a discrete tunneling of holes in porous silicon at room temperature are presented. The noise characteristics of diode structures with a porous silicon interlayer formed on heavily boron-doped silicon single crystals are studied. Peaks of excessive noise are observed at frequencies of ~1 MHz, at which single-electron oscillations should be expected. The peak noise power is found to increase with current according to the ~2.5 power law and, at a current density of 0.15 A/cm2, to exceed the noise power of the receiver by three to four orders of magnitude. The complex shape of the noise spectrum and its extension to the higher frequency region with increasing current are explained by the three-dimensionality of the system of nanometer-sized silicon grains embedded in insulating silicon dioxide of porous silicon.  相似文献   
108.
In this paper we study a stochastic differential equation with multivalued maximally monotone drift operator. Under certain assumptions on the growth of the multivalued operator we prove a theorem on the existence and uniqueness of the solution of such an equation.Translated fromTeoriya Sluchainykh Protsessov, Vol. 15, pp. 54–59, 1987.  相似文献   
109.
We develop a scheme based on pseudo-differential operators to analyze the propagation of excitations in inhomogeneous extended systems. This method is used in a very specific situation, however we think that it has some generality and should apply to various other problems of current interest. We study the well known two-dimensionalsymmetric model of solidification introduced by Langer and Turski. Assuming the existence of Ivantsov-like steady-state solutions, we calculate their excitation spectrum. We show that there are no unstable propagating modes if the Gibbs-Thomson effect is taken into account. This proves that the growth of needle-crystals is stable with respect to side-branching.  相似文献   
110.
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