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   589篇
  免费   2篇
  国内免费   1篇
教育   278篇
科学研究   270篇
各国文化   3篇
体育   3篇
文化理论   3篇
信息传播   35篇
  2023年   2篇
  2022年   7篇
  2021年   20篇
  2020年   5篇
  2019年   10篇
  2018年   37篇
  2017年   27篇
  2016年   24篇
  2015年   30篇
  2014年   28篇
  2013年   58篇
  2012年   21篇
  2011年   21篇
  2010年   26篇
  2009年   30篇
  2008年   28篇
  2007年   19篇
  2006年   33篇
  2005年   21篇
  2004年   15篇
  2003年   25篇
  2002年   12篇
  2001年   14篇
  2000年   10篇
  1999年   8篇
  1998年   11篇
  1997年   6篇
  1996年   3篇
  1995年   7篇
  1994年   5篇
  1993年   5篇
  1992年   5篇
  1991年   1篇
  1990年   1篇
  1989年   2篇
  1986年   2篇
  1985年   1篇
  1983年   2篇
  1979年   2篇
  1977年   2篇
  1976年   2篇
  1975年   2篇
  1973年   1篇
  1962年   1篇
排序方式: 共有592条查询结果,搜索用时 218 毫秒
71.
This study investigated the effect of Pen-Point and Powerbook computers on solving a multiple step chemistry (molaritý) problem among White, Afro-American and Hispanic students (N=60) at the high school level. The screens on both computers were partitioned into a work field and a reasoning field. Both computers were programmed to record the time spent in each field, the number of entries made, and a copy of the entries made. Statistical analysis of data showed that more of the White and Afro-American Pen-Point computer users solved the problem correctly than did students using the Powerbook computer. All three ethnic groups made fewer entries, and took less time using the Pen-Point computer than the Powerbook. Attitude survey results of all ethnic groups showed that more Pen-Point computer users felt comfortable working with computers. Over all, the results suggest that the Pen-Point computer has a more positive effect on the problem solving performance and attitude of students towards computers than the Powerbook computer.  相似文献   
72.
The ways computer technology could be used to teach science to students with learning disabilities (LD) are explored. Science is for all students and that includes students with LD. Learning science has both cognitive and affective implications for students with LD. In this context, computer technology provides cognitively engaging and motivating instructional tools for individualizing the mode of delivery; developing expert tutors; anchoring instruction; integrating science with other subjects; reducing cognitive load on working memory; and motivating students to stay on task. These applications are discussed with implications for teaching science to students with LD.  相似文献   
73.
An interesting and relevant case involving two distinct systematic evaluations, traditional as well as somewhat nontraditional, of a science teacher education project with a heavy technology emphasis is discussed. Comparisons of the two separate evaluations of the same project revealed the complexity of evaluating technology projects and the multifaceted ways in which the evaluation endeavor could be approached, and provided an unusual situation and seldom seen opportunity for thinking about such evaluations. Additionally, what some other authors have said about the evaluations of efforts that take advantage of technology in the training of science teachers will also be explored. Evaluators must become active players in guiding the infusion of technology in preservice science programs. If evaluators, don't function to identify what works and what doesn't and what induces the best supportive environment, then who will?  相似文献   
74.
The 2007 Nobel Prize in Physics was awarded to Albert Fert and Peter Grünberg for the discovery of giant magnetoresistance (GMR). GMR is achieved in metallic multilayers, where the resistance of the multilayer changes considerably by the application of a magnetic field. This has paved the way for high density data storage in magnetic media. (left) Debakanata Samal is a research scholar at the Deaprtment of Physics at IISc, Bangalore. His research interests are in magnetotransport in oxide multilayers, spintronics. (right) P S Anil Kumar is an Asst. Professor at the Department of Physics, IISc Bangalore. His research interests are in spintronics, magnetic nano-structures, surface-and thin-film magnetism, magnetotransport in metallic multilayers and oxides, and spin-polarized electron scattering.  相似文献   
75.
Lotka's law and institutional productivity   总被引:1,自引:0,他引:1  
The present study aims at determining the applicability of Lotka's law, negative binomial distribution and lognormal distribution for institutional productivity, in the same way as it is to authors and their productivity in the field of engineering sciences and the patents filed by industrial firms in laser S&T. The study indicates that non of the three distributions are applicable for institutional productivity in engineering sciences. However, Lotka's law holds good for full as well as truncated set of data for the patents filed by industrial firms.  相似文献   
76.
Satish Kumar 《Resonance》1999,4(4):45-55
In Part 1 of this article we understood the idea of a fuzzy set. We also reviewed simple operations such as fuzzy set intersection, union, and complementation, and related these to geometry. In Part 2, we extend the idea of fuzzy sets to explain how we may develop systems that reason with fuzzy sets using fuzzy logic. The idea of extending fuzzy logic to fuzzy engineering and fuzzy function approximation is explored with a working example. It is hoped that readers will be provided with enough motivation to appreciate the use of fuzzy set theory for real world applications.  相似文献   
77.
The present study was conducted to investigate the oxidant–antioxidant status in iron deficient pregnant anemic women. One hundred thirty pregnant women with iron deficiency anemia (IDA) were divided into three groups, namely mild (50), moderate (50) and severe (30) anemic along with pregnant healthy women as controls (50). The complete blood count, plasma lipid peroxidation products, enzymatic and non-enzymatic antioxidants were measured according to respective protocols. The levels of complete blood count, iron, ferritin along with antioxidant enzymes namely catalase, superoxide dismutase, glutathione peroxidase, glutathione reductase and reduced glutathione were significantly reduced in all IDA groups. However, the level of oxidized glutathione, lipid peroxides, protein carbonyls, conjugated dienes were found significantly increased in all anemic patients. Antioxidant vitamins, namely C, E and A were also found significantly decreased in IDA patients. On the basis of our results, it may be concluded that IDA tends to increase the pro-oxidant components, which may result in various complications including peroxidation of vital body molecules resulting in increased risk for pregnant women as well as fetus.  相似文献   
78.
The correlation between antioxidant capacity and oxidative damage during aging has been reported in several tissues in different species. Glutathione-S-transferases (GST) can metabolise endogenous and exogenous toxins and carcinogens by catalysing the conjugation of diverse electrophiles with reduced glutathione (GSH). We observe a significant (P < 0.001) increase in plasma GST activity as a function of human age (r = 0.5675). A significant (P < 0.001) positive correlation (r = 0.8979) is observed between GST activity and total plasma antioxidant potential measured as ferric reducing ability of the plasma (FRAP). GST activity and red cell intracellular GSH also show a significant positive correlation (r = 0.7014). We hypothesize that the increased activity of plasma GST is a manifestation of increased generation of ROS and a concomitant decrease in the level of plasma antioxidant capacity during aging.  相似文献   
79.
Every individual should be entrusted with an internal driver to strive their best towards achieving their potential and to manifest their performance through innovative means. This can be reached only under circumstances where the abstract human values and principles are recognized and indoctrinated in the culture. The strategies discussed in this article will serve as input in proposing the areas of focus toward the practice of human governance.  相似文献   
80.
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