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   1395篇
  免费   42篇
  国内免费   8篇
化学   796篇
晶体学   9篇
力学   64篇
数学   87篇
物理学   489篇
  2023年   23篇
  2022年   26篇
  2021年   49篇
  2020年   39篇
  2019年   37篇
  2018年   36篇
  2017年   35篇
  2016年   47篇
  2015年   36篇
  2014年   48篇
  2013年   114篇
  2012年   95篇
  2011年   121篇
  2010年   56篇
  2009年   46篇
  2008年   71篇
  2007年   69篇
  2006年   71篇
  2005年   55篇
  2004年   39篇
  2003年   35篇
  2002年   29篇
  2001年   17篇
  2000年   14篇
  1999年   9篇
  1998年   13篇
  1997年   15篇
  1996年   21篇
  1995年   18篇
  1994年   16篇
  1993年   9篇
  1992年   15篇
  1991年   5篇
  1990年   8篇
  1989年   8篇
  1988年   6篇
  1987年   2篇
  1986年   8篇
  1985年   11篇
  1984年   11篇
  1983年   8篇
  1982年   7篇
  1981年   4篇
  1980年   6篇
  1979年   9篇
  1978年   8篇
  1976年   4篇
  1975年   4篇
  1974年   3篇
  1969年   2篇
排序方式: 共有1445条查询结果,搜索用时 15 毫秒
961.
962.
963.
Job evaluation in fuzzy environment   总被引:1,自引:0,他引:1  
Job evaluation helps in developing and maintaining a pay structure based on values of the jobs. The job evaluation problem may be treated as managerial decision-making problem with multiple objectives. The present paper deals with the evaluation of a job in fuzzy environment. Fuzzy mathematical model has been developed for the job evaluation and solved with a suitable technique. A sample case study has been considered and the relative worth of various levels of job factors have been calculated numerically along with the scores of the benchmark jobs. An effort has been made to optimize the decision by maximizing the min operator.  相似文献   
964.
Powder neutron diffraction and Hi-Q neutron diffraction data have been recorded and analysed in order to obtain the local and long range order of Cu in Cudoped CeO2 with three doping levels of Cu. Rietveld method and MCGR techniques of data analysis for the two types of data reveal that the Cu ion is in the 2+ oxidation state and has a vacancy in its first coordination shell. These deductions from the data analysis fit well with the mechanism of catalysis we propose.  相似文献   
965.
Colloidal nanodispersion of lead sulfide has been prepared in the aqueous compartments of water/AOT/n-heptane. Compartmentalization has prevented growth and coagulation of particles in the dispersion. The uv–vis and fluorescence spectral measurements of the colloidal PbS dispersion were taken. Particle size has been determined by laser light scattering, transmission electron microscopy and absorption spectroscopy. The effects of temperature, ω (water/AOT mole ratio), [AOT], and [PbS] on the particle size have been examined. The nanodispersed particles in microemulsion capped with thiophenol and dodecanethiol were isolated and characterized by the TEM and FTIR methods.  相似文献   
966.
We develop string cosmology in the presence ofa Brans–Dicke (BD) scalar field coupled toEinstein gravity for higher dimensional space-time.Solutions are obtained for the equation of state for thep-string, and physical situations arediscussed.  相似文献   
967.
In this paper, generalization of a vertical block linear complementarity problem associated with two different types of matrices, one of which is a square matrix and the other is a vertical block matrix, is proposed. The necessary and sufficient conditions for the existence of the solution of the generalized vertical block linear complementarity problem is derived and the relationship between the solution set of the generalized vertical block linear complementarity problem and the linear complementarity problem is established. It is proved that the generalized vertical block linear complementarity problem has the P-property if and only if the vertical block linear complementarity problem has the P-property.  相似文献   
968.
State-of-the-art semiconductor devices require accurate control of the full two-dimensional dopant distribution. In this work, we report results obtained on 2D electrical characterization of ultra shallow junctions in Si using off axis electron holography to study two-dimensional effects on diffusion. In particular, the effect of a nitride diffusion mask on lateral diffusion of phosphorous is discussed. Retardation of lateral diffusion of P under the nitride diffusion mask is observed and compared to the lateral diffusion of P under an oxide diffusion mask. The ultra shallow junctions for the study were fabricated by a rapid thermal diffusion process from heavily P doped spin-on-dopants into a heavily B doped Si substrate. These shallow junctions are needed for fabricating source/drain extensions in nanoscale MOSFETs. One-dimensional electrical characterization of the junction was carried out to determine the electrical junction depth and compared to the metallurgical junction depth from SIMS analysis.  相似文献   
969.
970.
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