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   1764篇
  免费   92篇
  国内免费   11篇
化学   1309篇
晶体学   46篇
力学   55篇
数学   120篇
物理学   337篇
  2023年   20篇
  2022年   39篇
  2021年   96篇
  2020年   59篇
  2019年   61篇
  2018年   92篇
  2017年   66篇
  2016年   90篇
  2015年   69篇
  2014年   71篇
  2013年   152篇
  2012年   142篇
  2011年   139篇
  2010年   87篇
  2009年   72篇
  2008年   88篇
  2007年   73篇
  2006年   45篇
  2005年   39篇
  2004年   34篇
  2003年   34篇
  2002年   54篇
  2001年   35篇
  2000年   44篇
  1999年   11篇
  1998年   18篇
  1997年   10篇
  1996年   6篇
  1995年   10篇
  1994年   5篇
  1993年   6篇
  1992年   5篇
  1991年   4篇
  1990年   10篇
  1989年   8篇
  1988年   5篇
  1987年   6篇
  1986年   3篇
  1985年   4篇
  1984年   6篇
  1983年   4篇
  1982年   4篇
  1981年   3篇
  1980年   6篇
  1979年   7篇
  1978年   6篇
  1977年   4篇
  1976年   2篇
  1974年   2篇
  1937年   2篇
排序方式: 共有1867条查询结果,搜索用时 484 毫秒
1.
2.
3.
Journal of Thermal Analysis and Calorimetry - The operating temperature of Li-ion batteries used in modern electric vehicles should be maintained within an allowable range to avoid thermal runaway...  相似文献   
4.
LetP(z) be a polynomial of degreen which does not vanish in |z|<1. In this paper, we estimate the maximum and minimum moduli of thekth polar derivative ofP(z) on |z|=1 and thereby obtain compact generalizations of some known results, which among other results, yields interesting refinements of Erdos-Lax theorem and a theorem of Ankeny and Rivlin.  相似文献   
5.
A mathematical model of laser beam treatment of double layer alloys (Ni/Fe, Al/Fe and Cr/Fe systems) describing the effect of laser beam on different physical and geometrical parameters of coated layer system has been adapted. The numerical solutions of the non-homogeneous heat-transport differential equation could estimate the temperature of the treated region.The suggested model allows investigation of the temperature distribution as a function of treated surface and laser parameters. The physical parameters of the treated materials were taken as functions of temperature due to the change in the temperature of the treated double layer materials.  相似文献   
6.
This paper deals with the study of the MHD flow of non-Newtonian fluid on a porous plate. Two exact solutions for non-torsionally generated unsteady hydromagnetic flow of an electrically conducting second order incompressible fluid bounded by an infinite non-conducting porous plate subjected to a uniform suction or blowing have been analyzed. The governing partial differential equation for the flow has been established. The mathematical analysis is presented for the hydromagnetic boundary layer flow neglecting the induced magnetic field. The effect of presence of the material constants of the second order fluid on the velocity field is discussed.  相似文献   
7.
In this paper we establish a sharp result concerning integral mean estimates for self-reciprocal polynomials.  相似文献   
8.
Curvature collineations are symmetry directions for the Riemann tensor, as isometries are for the metric tensor and Ricci collineations are for the Ricci tensor. Complete listings of many metrics possessing some minimal symmetry have been given for a number of symmetry groups for the latter two symmetries. It is shown that a claimed complete listing of cylindrically symmetric static metrics by their curvature collineations [1] was actually incomplete and is completed here. It turns out that in this complete list, unlike the previous claim, there are curvature collineations that are distinct from the set of isometries and of Ricci collineations. The physical interpretation of some of the metrics obtained is given.  相似文献   
9.
The scaled factorial moments and the multifractal moments have been investigated in differentη-intervals to study the dynamical fluctuation of pions produced in 200 AGeV32S-Ag/Br interaction. In order to investigate the detail characteristics of intermittency behaviour, theF-moments are extracted up to the eighth order of moments in differentM-intervals. The analysis indicates a non-thermal phase transition and different regime of particle production during the hadronisation process.  相似文献   
10.
In the title compound, C18H13BrClNO3, the heterocyclic ring of the indole is distorted from planarity towards an envelope conformation. The orientations of the indole, oxetane, chloro and bromo­phenyl substituents are conditioned by the sp3 states of the spiro‐junction and the Cl‐attached C atoms.  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