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   608篇
  免费   11篇
  国内免费   8篇
教育   424篇
科学研究   63篇
各国文化   2篇
体育   62篇
综合类   64篇
信息传播   12篇
  2022年   2篇
  2021年   7篇
  2020年   7篇
  2019年   5篇
  2018年   5篇
  2017年   13篇
  2016年   8篇
  2015年   15篇
  2014年   38篇
  2013年   40篇
  2012年   39篇
  2011年   44篇
  2010年   33篇
  2009年   30篇
  2008年   29篇
  2007年   38篇
  2006年   48篇
  2005年   46篇
  2004年   30篇
  2003年   37篇
  2002年   33篇
  2001年   14篇
  2000年   24篇
  1999年   13篇
  1998年   6篇
  1997年   3篇
  1996年   3篇
  1995年   4篇
  1994年   2篇
  1993年   2篇
  1992年   5篇
  1991年   2篇
  1990年   1篇
  1989年   1篇
排序方式: 共有627条查询结果,搜索用时 0 毫秒
51.
以家庭和男女情感为主要题材的情节剧电影在中西电影中占有很大的比重,它关注人们的情感,反映时代的变化,具有很大的社会反响。文章从妇女在家庭中的地位、夫妻的心理错位,以及个人价值的追求与家庭生活的矛盾等方面对克莱默夫妇的家庭悲剧进行深入的探究,旨在对女性与自我价值的的问题提出自我的思考。  相似文献   
52.
As a special geological phenomenon, the character of collapsible loess foundation is collapsible when penetrated by water. This character leads to the soil losing load bearing capacity largely and may lead to foundation failure. Pile is a popular foundation used in collapsible loess. The squeezed branch and plate pile is a new type of pile developed in recent years and has not be used in a project before. In this paper three squeezed branch and plate piles are tested in collapsible loess after immersion processing. The results may be used for reference in similar construction project, and to provide theoretical references for de- signing of the squeezed branch and plate piles in engineering practice.  相似文献   
53.
设计了一种利用弹性铰链作为预紧机构、高精度滚动导轨作为导向机构的单PZT驱动的微进给平台。利用有限元方法对微进给平台的结构和静、动态特性进行了研究。在静态特性中着重分析了微进给平台的静态刚度,得出整个动平台的工作平面上的刚度分布图。在动态特性分析中着重研究了微进给平台的模态振型、固有频率和谐波激励响应,得出了激进给平台在动态激振力作用下的特性。最后分析了微进给平台工作平面上静态刚度和动态刚度变化很大的原因,并提出一些改进的措施。  相似文献   
54.
通过工程实践 ,提出钢筋混凝土预制方桩采用静力压桩施工质量监理工作方法  相似文献   
55.
According to the definition of the new hypothetical states which have obvious physical sig-nificance and are termed as no-gravity static and accelerated states, a method for exact computa-tion of the parallel robot's generalized inertia matrix is presented. Based on the matrix theory, the generalized inertia matrix of the parallel robot can be computed on the assumption that the robot is in these new hypothetical states respectively. The approach is demonstrated by the Delta robot as an example. Based on the principle of the virtual work, the inverse dynamics model of the robot is formulized after the kinematics analysis. Finally, a numerical example is given and the element dis-tribution of the Delta robot's inertia matrix in the workspace is studied. The method has computational advantage of numerical accuracy for the Delta robot and can be parallelized easily.  相似文献   
56.
通过对静电场描绘实验两种方法的对比分析,指出其优缺点,并给出提高测量精度的方法。  相似文献   
57.
1 Introduction Organic semiconductors are receiving considerableattention due to their remarkable advantages especiallyvarious manufacturing methods ,lowcost and plentifulmaterials .Ebisawa ,et al.[1]fabricated the first poly-mer-based transistor in 1983 . Since then,lots of re-search works have been done in the filed of organicmaterial-based transistors .It was reported that organicthin-fil m transistor ( OTFT) fabricated by usingorganic semiconductor material copper-phthalocyanine(CuPc)[2…  相似文献   
58.
Using data from a sample of 10 colleges at which most students had taken both SAT I: Reasoning tests and SAT II: Subject tests, we simulated the effects of making selection decisions using SAT II scores in place of SAT I scores. Specifically, we treated the students in each college as forming the applicant pool for a more select college, and then selected the top two thirds (and top one third) of the students using high school grade point average combined with either SAT I scores or the average of SAT II scores. Success rates, in terms of first-year grade point averages, were virtually identical for students selected by the different models. The percentage of African American, Asian American, and White students selected varied only slightly across models. Appreciably more Mexican American and Other Latino students were selected with the model that used SAT II scores in place of SAT I scores because these students submitted subject test scores for the Spanish test on which they had high scores.  相似文献   
59.
本文从作用域和生命周期的角度解析了静态全局变量、静态局部变量、静态数据成员的含义,指出了它们本质上的特点和区别。  相似文献   
60.
对近年来数学各领域之间、数学与物理之间的相互影响再次活跃,并相互作用及产生的重要成果进行了讨论,同时强调了数学的统一性。  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