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   407篇
  免费   75篇
  国内免费   33篇
化学   126篇
晶体学   4篇
力学   58篇
综合类   7篇
数学   253篇
物理学   67篇
  2024年   2篇
  2023年   5篇
  2022年   3篇
  2021年   6篇
  2020年   13篇
  2019年   23篇
  2018年   16篇
  2017年   20篇
  2016年   28篇
  2015年   26篇
  2014年   20篇
  2013年   31篇
  2012年   17篇
  2011年   23篇
  2010年   12篇
  2009年   20篇
  2008年   17篇
  2007年   22篇
  2006年   23篇
  2005年   15篇
  2004年   23篇
  2003年   22篇
  2002年   14篇
  2001年   17篇
  2000年   22篇
  1999年   15篇
  1998年   16篇
  1997年   9篇
  1996年   10篇
  1995年   2篇
  1994年   7篇
  1993年   1篇
  1992年   3篇
  1991年   2篇
  1990年   1篇
  1989年   1篇
  1988年   4篇
  1987年   1篇
  1979年   1篇
  1977年   1篇
  1957年   1篇
排序方式: 共有515条查询结果,搜索用时 15 毫秒
71.
彩虹全息图的假彩色编码方法   总被引:2,自引:0,他引:2  
本文在三基色原理的基础上,分析了在彩虹全息术中的两种假彩色编码方法——多狭缝假彩色编码方法和参考光假彩色编码方法。  相似文献   
72.
具有两次透射的无光焦度校正透镜组的准施密特系统   总被引:2,自引:1,他引:1  
史光辉 《光学学报》1998,18(3):73-375
介绍了一种具有两次透射的无光焦度校正透镜组的准施密特系统及其设计思想和方法,并给出了一个设计结果。焦距2.7m,相对孔径F/5.5,视场角3.42°。在全视场范围内成像质量达到了衍射极限。  相似文献   
73.
胡长松 《应用数学》1998,11(1):101-105
本文给出了L_p空间中渐近次收缩映象Mann迭代过程收敛性定理.  相似文献   
74.
This paper gives an explicit formula for calculating the Webster pseudo torsion for a strictly pseudoconvex pseudo-hermitian hypersurface. As applications, we are able to classify some pseudo torsion-free hypersurfaces, which include real ellipsoids.  相似文献   
75.
This paper studies regression, where the reciprocal of the mean of a dependent variable is considered to be a linear function of the regressor variables, and the observations on the dependent variable are assumed to have an inverse Gaussian distribution. The large sample theory for the pseudo maximum likelihood estimators is available in the literature, only when the number of replications increase at a fixed rate. This is inadequate for many practical applications. This paper establishes consistency and derives the asymptotic distribution for the pseudo maximum likelihood estimators under very general conditions on the design points. This includes the case where the number of replications do not grow large, as well as the one where there are no replications. The bootstrap procedure for inference on the regression parameters is also investigated.Research supported in part by NSF Grant DMS-9208066.Research supported in part by NSERC of Canada.  相似文献   
76.
Vector-valued pseudo almost periodic functions are defined and their properties are investigated. The vector-valued functions contain many known functions as special cases. A unique decomposition theorem is given to show that a vector-valued pseudo almost periodic function is a sum of an almost periodic function and an ergodic perturbation.  相似文献   
77.
V K B Kota 《Pramana》1977,9(2):129-140
The single particle SU(3) parentage coefficients are calculated for the case of leading SU(3) representation in the highest orbital symmetry partition, using the method suggested by Hecht. Tabulations are given for all possible cases of identical nucleons in η=3 and η=4 shells.  相似文献   
78.
79.
Blocking is often used to reduce known variability in designed experiments by collecting together homogeneous experimental units. A common modeling assumption for such experiments is that responses from units within a block are dependent. Accounting for such dependencies in both the design of the experiment and the modeling of the resulting data when the response is not normally distributed can be challenging, particularly in terms of the computation required to find an optimal design. The application of copulas and marginal modeling provides a computationally efficient approach for estimating population‐average treatment effects. Motivated by an experiment from materials testing, we develop and demonstrate designs with blocks of size two using copula models. Such designs are also important in applications ranging from microarray experiments to experiments on human eyes or limbs with naturally occurring blocks of size two. We present a methodology for design selection, make comparisons to existing approaches in the literature, and assess the robustness of the designs to modeling assumptions.  相似文献   
80.
In this study, we focus on the solutions of the Li\''enard equation being bounded in the future and characterize the almost automorphic, asymptotically almost automorphic, and weighted pseudo almost automorphic dynamics. An example is presented to illustrate the main findings.  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