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   1293篇
  免费   31篇
  国内免费   11篇
化学   970篇
晶体学   24篇
力学   26篇
数学   111篇
物理学   204篇
  2022年   5篇
  2021年   12篇
  2020年   8篇
  2019年   18篇
  2018年   10篇
  2017年   18篇
  2016年   23篇
  2015年   15篇
  2014年   34篇
  2013年   52篇
  2012年   58篇
  2011年   83篇
  2010年   32篇
  2009年   45篇
  2008年   60篇
  2007年   64篇
  2006年   65篇
  2005年   83篇
  2004年   77篇
  2003年   64篇
  2002年   53篇
  2001年   29篇
  2000年   31篇
  1999年   6篇
  1998年   21篇
  1997年   20篇
  1996年   22篇
  1995年   12篇
  1994年   18篇
  1993年   21篇
  1992年   9篇
  1991年   19篇
  1990年   16篇
  1989年   15篇
  1988年   16篇
  1987年   16篇
  1986年   17篇
  1985年   18篇
  1984年   25篇
  1983年   8篇
  1982年   13篇
  1981年   12篇
  1980年   15篇
  1979年   10篇
  1978年   8篇
  1977年   9篇
  1975年   7篇
  1974年   8篇
  1973年   5篇
  1963年   5篇
排序方式: 共有1335条查询结果,搜索用时 234 毫秒
1.
A computer code for simulation of beam-field interaction in a resonant cavity of a gyrotron has been developed. It is based on a self-consistent, time-independent, single-mode physical model. The code has been applied to the analysis of the electrodynamical system of a novel high-harmonic gyrotron with axis-encircling beam and a permanent magnet. In this paper both the physical model and numerical techniques used are outlined. Some results of the numerical experiments are presented and discussed.  相似文献   
2.
We introduce a new scheme for the future application of Real-coded Lattice Gas (RLG) to the numerical simulation of suspended solid objects in a fluctuating fluid environment. The reproduction of Brownian motion for a single solid object is verified through the Gaussian distribution of its displacements. The effectiveness of the solid–solid interaction model is also confirmed in an N-body simulation.  相似文献   
3.
The photocatalytic reactivities of chromium-containing mesoporous silica molecular sieves (Cr-HMS) under visible light irradiation have been investigated. Cr-HMS involves tetrahedral chromium oxide (Cr-oxide) moieties which are highly dispersed and incorporated in the framework of molecular sieve with two terminal Cr=O groups. In the presence of propane with molecular oxygen, a partial oxidation proceeded under visible light irradiation to produce acetone and acrolein, with high selectivity, while a complete oxidation proceeded under UV light irradiation mainly to produce CO2. The charge-transfer excited state of the tetrahedral Cr-oxide moieties plays a significant role in the photocatalytic reactions.  相似文献   
4.
5.
Heat transfer in lattice BGK modeled fluid   总被引:1,自引:0,他引:1  
The thermal lattice BGK model is a recently suggested numerical tool aiming at solving problems of thermohydrodynamics. The quality of the lattice BGK simulation is checked in this paper by calculating temperature profiles in the Couette flow under different Eckert and Mach numbers. A revised lower order model is proposed to improve the accuracy and the higher order model is proved to be advantageous in this respect, especially in the flow regime with a higher Mach number.  相似文献   
6.
A modified light-fluorous Mukaiyama reagent bearing a C8F17 tag was prepared and examined in ester and amide forming condensation reactions. Following the reactions, the desired product was effectively separated from the fluorous pyridone by-product using a simple fluorous solid phase extraction.  相似文献   
7.
8.
In this paper, we introduce an affine scaling algorithm for semidefinite programming (SDP), and give an example of a semidefinite program such that the affine scaling algorithm converges to a non-optimal point. Both our program and its dual have interior feasible solutions and unique optimal solutions which satisfy strict complementarity, and they are non-degenerate everywhere.  相似文献   
9.
The Heat Kernel on Hyperbolic Space   总被引:1,自引:0,他引:1  
The purpose of this note is to provide a new proof for the explicitformulas of the heat kernel on hyperbolic space. By definition,the hyperbolic space Hn is a (unique) simply connected completen-dimensional Riemannian manifold with a constant negative sectionalcurvature –1. 1991 Mathematics Subject Classification58G32, 58G11.  相似文献   
10.
Collagen-containing tubular giant vesicles (Col–tGVs) under a high static magnetic field were found to constitute characteristic curved structures (e.g. circular, 8-figure, and hairpin-loop), which were sustained by polymerization of collagen units inside the tGV. We ascribed the formation of these structures to the elasticity of the tGV and to the competing diamagnetic anisotropies between collagen and the tGV. These curved structures can be well expressed by the equation of elastica.  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