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   319篇
  免费   10篇
  国内免费   1篇
教育   153篇
科学研究   129篇
各国文化   3篇
体育   16篇
文化理论   2篇
信息传播   27篇
  2023年   5篇
  2022年   6篇
  2021年   10篇
  2020年   14篇
  2019年   13篇
  2018年   37篇
  2017年   23篇
  2016年   13篇
  2015年   22篇
  2014年   29篇
  2013年   28篇
  2012年   18篇
  2011年   14篇
  2010年   11篇
  2009年   17篇
  2008年   13篇
  2007年   9篇
  2006年   4篇
  2005年   10篇
  2004年   1篇
  2003年   2篇
  2002年   1篇
  2001年   2篇
  2000年   1篇
  1998年   3篇
  1996年   1篇
  1994年   1篇
  1990年   2篇
  1988年   2篇
  1987年   1篇
  1985年   1篇
  1984年   1篇
  1983年   2篇
  1982年   4篇
  1981年   2篇
  1980年   1篇
  1975年   1篇
  1973年   2篇
  1963年   2篇
  1961年   1篇
排序方式: 共有330条查询结果,搜索用时 15 毫秒
61.
The Department of Mechanical Engineering at our institution created two engineering courses for the General Education Program that count towards second level general science credit (traditional science courses are first level). The courses were designed for the general student population based upon the requirements of our General Education Program and engineering concepts. We explain the results and impact of the classes so as to expand the conceptualization of general education courses and to enable engineering curricula to reach a larger audience as well as to broaden student understanding of the forces shaping their world.  相似文献   
62.
In this paper we introduce a novel approach, relying on intelligent engineering, whereby the maximum speed limit at which vehicles on the road can cruise is controlled from some central or distributed facility. The system, as designed, leverages the use of the ubiquitous cellular infrastructure to cut down the costs involved that would otherwise accrue as a result of the need to build a dedicated traffic control system.In the new system maximum speed limits are transmitted from a Central Control Facility (CCF) to all stretches of roads and highways dispersed across urban areas in a highly dynamic manner. The system uses information arriving via a dynamic feedback system on prevailing weather conditions, road conditions, and bulk of traffic, amongst others, before it would broadcast maximum speed limit information to various destinations. When deployed in its final release, this will be done using a highly automated system with little human intervention.The work presented in this paper elaborates the TTC Network Design and RSU Network Distribution for the Tele-Traffic Speed Control System, to remotely manage, enforce, and control the maximum speed limit allowed on road stretches in rural and urban areas for different vehicle categories.The new system has been deployed successfully in a laboratory controlled environment on three vehicle categories; one category representing passenger vehicles, another buses and commuter transport, while the third representing trucks and freight traffic. It is expected that when the system is fully deployed on the wireless infrastructure, speed-related traffic accidents will witness a drop by more than 65-70% according to known accident statistics.  相似文献   
63.
Taxonomy of e-readiness assessment measures   总被引:1,自引:0,他引:1  
To benefit from the advantages of information society, on the one hand, and to be afraid of being left further behind by Global Society and the increase in the digital divide, on the other hand, stimulate countries to be part of Global Information Society. These issues have led policymakers to move towards such a society by identifying the objectives, goals and targets. Planning to achieve these objectives needs a real understanding of the current situation, which is obtained by e-readiness assessment measures. There has been a proliferation of e-readiness assessment measures in recent years that each one has a certain objective. This paper elaborates on and categorizes these measures that help scholars and policymakers to (1) select the measures that fit in with their objectives, (2) prevent the repetitive research, (3) identify the defects and flaws of previous measures and correct them in their own measures, and (4) use the experiences of previous measures to construct their own ones. Based on definitions, objectives, dimensions, methods and approaches, in this paper, the measures are categorized and finally, a measure for e-readiness assessment is presented. Since this measure is a convergence of e-readiness assessment measures, the experienced modelers have consensus on it and it is more suitable to measure e-readiness of countries. Also, it can be exploited as the basis and standard for internationally comparable information society statistics.  相似文献   
64.
A fast and efficient page ranking mechanism for web crawling and retrieval remains as a challenging issue. Recently, several link based ranking algorithms like PageRank, HITS and OPIC have been proposed. In this paper, we propose a novel recursive method based on reinforcement learning which considers distance between pages as punishment, called “DistanceRank” to compute ranks of web pages. The distance is defined as the number of “average clicks” between two pages. The objective is to minimize punishment or distance so that a page with less distance to have a higher rank. Experimental results indicate that DistanceRank outperforms other ranking algorithms in page ranking and crawling scheduling. Furthermore, the complexity of DistanceRank is low. We have used University of California at Berkeley’s web for our experiments.  相似文献   
65.
Free iron in serum has been found in several disease conditions including diabetes. In the present work, we studied the relationship between free iron, fasting blood glucose (FBG) and glycated haemoglobin (HbA1c). Study was carried out on 50 type 2 diabetes cases under poor glycemic control associated with complications, 53 type 2 diabetes cases under good glycemic control and 40 healthy controls. We estimated free iron, both ferrous (Fe+2) and ferric (Fe+3) form, protein thiols, lipid hydroperoxides, FBG, HbA1c and serum ferritin levels in serum. There was a significant increase in free iron in Fe+3 state (p <0.01), HbA1c (p<0.01), serum ferritin (p<0.01), lipid hydroperoxides (p<0.01) and significant decrease in protein thiols (<0.01) in diabetes cases under poor glycemic control compared to diabetes cases under good glycemic control and healthy controls. Free iron correlated positively with HbA1c (p<0.01). Poor glycemic control and increase in glycation of haemoglobin is contributing to the increase in free iron pool which is known to increase oxidant generation.  相似文献   
66.
The ever increasing presence of online social networks in users’ daily lives has led to the interplay between users’ online and offline activities. There have already been several works that have studied the impact of users’ online activities on their offline behavior, e.g., the impact of interaction with friends on an exercise social network on the number of daily steps. In this paper, we consider the inverse to what has already been studied and report on our extensive study that explores the potential causal effects of users’ offline activities on their online social behavior. The objective of our work is to understand whether the activities that users are involved with in their real daily life, which place them within or away from social situations, have any direct causal impact on their behavior in online social networks. Our work is motivated by the theory of normative social influence, which argues that individuals may show behaviors or express opinions that conform to those of the community for the sake of being accepted or from fear of rejection or isolation. We have collected data from two online social networks, namely Twitter and Foursquare, and systematically aligned user content on both social networks. On this basis, we have performed a natural experiment that took the form of an interrupted time series with a comparison group design to study whether users’ socially situated offline activities exhibited through their Foursquare check-ins impact their online behavior captured through the content they share on Twitter. Our main findings can be summarised as follows (1) a change in users’ offline behavior that affects the level of users’ exposure to social situations, e.g., starting to go to the gym or discontinuing frequenting bars, can have a causal impact on users’ online topical interests and sentiment; and (2) the causal relations between users’ socially situated offline activities and their online social behavior can be used to build effective predictive models of users’ online topical interests and sentiments.  相似文献   
67.
68.
69.
The history of using tiles in Persian architecture dates back to the eleventh century. In the beginning, tiles were made of bricks and mounted with plaster. Thereafter, however, tiles were replaced with mosaics to decorate buildings. The technique of applying mosaics began in the thirteenth century and reached its summit during the Ilkhanid and Timurid periods between the fourteenth to sixteenth centuries. One of the most outstanding buildings in which mosaics were widely used is Ghaffarieh Dome, a fourteenth-century building in Maragheh, Eastern Azerbaijan. The Dome is especially noteworthy for its unique mosaic workings. Therefore, a thorough examination of the mosaics used in the Dome may pave the way for closer studies of the Ilkhanid mosaics (tile-workings) in Iran. Since there is little information on the material aspects of mosaics used in the Ghaffarieh Dome, the body and glaze of the mosaics were examined through instrumental analyses. In order to interpret the results of the analyses, they were compared with existing data about similar mosaics of Islamic lands. The presence of pyroxene (aluminum diopside) in some of the mosaic bodies revealed that the firing temperature limit in the kiln was not, most likely, uniform. Two kinds of glazes, alkaline and lead-based, were used to produce black and turquoise colors.  相似文献   
70.
The current status of academic publishing is worrying. Cybercriminals are now targeting academic audiences, making it necessary to inform both editors and authors about such issues. The latest involves bogus impact factors, which are challenging scholarly publishing. Legitimate impact factors are used by authors and editors to get a general idea of the audience, if any, for a particular piece or journal. The bogus metrics only add confusion in support of the cybercrimes of their initiators. In this paper, we discuss bogus impact factors, victim countries, and try to clarify the phenomena for both authors and editors.  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