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   1833篇
  免费   29篇
  国内免费   16篇
教育   1298篇
科学研究   222篇
各国文化   23篇
体育   185篇
综合类   28篇
文化理论   16篇
信息传播   106篇
  2022年   19篇
  2021年   28篇
  2020年   41篇
  2019年   50篇
  2018年   72篇
  2017年   71篇
  2016年   68篇
  2015年   41篇
  2014年   50篇
  2013年   252篇
  2012年   63篇
  2011年   46篇
  2010年   42篇
  2009年   47篇
  2008年   44篇
  2007年   59篇
  2006年   66篇
  2005年   55篇
  2004年   53篇
  2003年   95篇
  2002年   125篇
  2001年   118篇
  2000年   67篇
  1999年   25篇
  1998年   14篇
  1997年   19篇
  1996年   11篇
  1995年   14篇
  1994年   12篇
  1993年   16篇
  1992年   10篇
  1991年   10篇
  1990年   11篇
  1989年   5篇
  1988年   4篇
  1987年   10篇
  1986年   5篇
  1985年   10篇
  1984年   10篇
  1983年   5篇
  1982年   8篇
  1980年   5篇
  1978年   9篇
  1974年   6篇
  1973年   4篇
  1969年   4篇
  1967年   4篇
  1890年   5篇
  1889年   8篇
  1865年   4篇
排序方式: 共有1878条查询结果,搜索用时 218 毫秒
991.
Communicating complex scientific and technical information presents a challenge for food science educators. The most efficient learning occurs when all senses are engaged, one reason that many educators believe that scientific principles are best taught with hands‐on laboratory experiences. Today there are many challenges to the continuation of these “wet labs” including the cost of building the labs as well as equipment, materials, and personnel to run them. Many current e‐learning technologies are based on 2‐dimensional delivery systems, and are often inadequate to provide a substitute for a laboratory exercise. However, recent advances in technology have evolved to more closely reflect the kinds of learning experiences that students typically have in a laboratory class. This review describes the role of these emerging technologies as teaching tools for educators, with the clear understanding that similar concepts can be utilized by management of technical teams in the work place.  相似文献   
992.
以转IrrE基因油菜为材料,以非转基因油菜为对照,砂培条件下研究了油菜对Cs的积累吸收情况和Cs胁迫对油菜SOD、POD酶活性、MDA含量及游离脯氨酸含量的影响.结果表明:随着处理浓度的增大,转基因油菜和非转基因油菜对Cs的吸收量都增大,二者根部的吸收量都大于其地上部分;转基因油菜根部的积累量大于非转基因油菜根部的量,而地上部分积累量小于非转基因油菜的含量;在不同Cs浓度的胁迫下,转基因和非转基因叶片的SOD和POD活性均呈现先升后降的趋势,4种Cs浓度处理下转基因油菜活性都高于非转基因油菜;转基因和非转基因油菜叶片的MDA含量均呈上升的趋势,但转基因油菜体内的MDA含量都低于非转基因油菜;4种处理下油菜叶片脯氨酸含量也表现出上升趋势,而转基因油菜产生的游离脯氨酸高于非转基因产生的.以上结果说明在油菜受到Cs胁迫时,转IrrE基因油菜比非转基因油菜更具有Cs胁迫耐受性.  相似文献   
993.
De Moortel  Kevin  Crispeels  Thomas  Xie  Jinyu  Jing  Qiaosong 《Minerva》2022,60(1):29-55

Temporary international mobility is an increasingly relevant practice amongst academics. However, current literature lacks understanding on whether such mobility influences the individual academics’ entrepreneurial knowledge. This paper hypothesizes that temporary international academic mobility is conducive to the academic’s entrepreneurial knowledge and that interpersonal social networks play a crucial role in the transfer of this knowledge through their strength and size properties. We perform a Partial Least Squares - Structural Equation Model and build upon an original survey data set collected amongst 281 Chinese academics. We find that the size of one’s interpersonal social network fully mediates the relationship between international academic mobility and entrepreneurial knowledge. This result points to the importance of a structurally broad - rather than a relationally strong - international social network in the academic’s accumulation of entrepreneurial knowledge abroad.

  相似文献   
994.
This paper investigates how pupils' growth trajectories in three language domains (reading fluency, spelling, and reading comprehension) are related to their own socioeconomic and ethnic background and to the socioeconomic and ethnic composition of their primary school. Using multilevel piecewise growth curve analysis, the growth trajectories of approximately 5000 pupils from 170 primary schools were estimated. The results indicate that a pupil's socioeconomic and ethnic backgrounds have the largest impact on achievement and growth in reading comprehension and the smallest impact on reading fluency. Furthermore, school ethnic composition—but not socioeconomic composition—was related to pupils' achievement in all three language domains at the first measurement occasion, though none of the types of school composition was related to growth. The research findings therefore imply that to combat the deficits in language proficiency often found in ethnic minority pupils, priority should be given to investments in individual intervention programmes over policy plans to desegregate schools. Moreover, our study identifies the specific points in time during primary school at which intervention programmes are needed the most.  相似文献   
995.
This study examines the influence of personality traits, goal orientation and self-efficacy on high school teachers’ participation in learning activities in the workplace (i.e. experimentation, informal interaction with colleagues, self-regulation and avoidance behaviour). A convenience sample of 95 teachers from six high schools in Flanders (Belgium) participated in this exploratory study. They completed a questionnaire consisting of different instruments to map their personality (NEO-FFI), goal orientation (adaptation of Achievement Goal Questionnaire), self-efficacy (Teachers’ Sense of Efficacy Scale) and participation in learning activities (adaptations from different scales). Results of multivariate regression analyses indicate that conscientiousness, extraversion and openness have a positive effect on teachers’ participation in learning activities in the workplace. However, learning orientation and self-efficacy are found to be better predictors for participation in experimentation, informal interaction and selfregulation. Analysis using structural equation modeling reveals an indirect relationship between extraversion and self-regulation, mediated by self-efficacy. Learning orientation mediates the impact of conscientiousness on informal interaction. As teachers’ goal orientation and self-efficacy can be influenced, school policy makers should reflect upon ways on how teachers’ goal orientation and self-efficacy can further be enhanced.  相似文献   
996.
基于卷取机在连退生产线的重要性,分析卷取机的机械结构,研究卷取机的控制系统。通过实际应用,说明采用间接张力控制的最大转矩法来实现卷取机系统的恒张力是有效的。  相似文献   
997.
For its fifteenth anniversary, the Jay Sexter Library at Touro University Nevada (TUN) sought ways to capture its institutional history by founding an archive. Among many challenges, the library struggled to convince the administration of the importance of an archive. To generate interest in TUN''s history, a task force comprising library, executive administration, and advancement staff hosted and recorded a panel event with some of the university''s original faculty, staff, and administration. By having this event, new TUN employees were able to experience the shared knowledge of TUN''s early days, and the library was able to create and preserve its own institutional history.  相似文献   
998.
Few studies have investigated the psychometric property of new instruments developed locally to assess students' library experience, such as their behavior, perception and attitude toward library use. Validating a survey instrument is critical because using untested assessment instruments is more likely to lead to a lack of credibility in the results, as well as a lack of accuracy in the study's purpose (Sullivan, 2011). This study used data from a locally developed student library experience survey distributed in Spring 2018 at a large public research university library to examine undergraduate and graduate students' behaviors, attitudes and perceptions of library use. To test the validity of the survey as to whether six subdomains of the library experience survey contributed to a single construct, library experience, the study used Rasch model framework. This study contributes to the field as a first example using the Rasch model for library assessment purposes. Suggestions for best practices are discussed.  相似文献   
999.
传统注意力测验是以纸笔的形式进行测试。本研究依据陈国鹏等人编制的《中小学生注意力测验》所得五个因子:注意的稳定性、注意的广度、注意的转移、注意的持续性、注意的集中性开发了"儿童注意力品质游戏测验软件"。经检验,该软件有较好的信度和效度。它不仅可用于普通学生及注意缺陷儿童的注意测评,同时也可用该技术对学生进行注意力训练,从而提高注意缺陷儿童及普通学生的注意力品质。  相似文献   
1000.
Citation Needed     
The ability to add hyperlinks to a news story is a key feature of online news. In addition to the—aging—technical novelty, one can wonder what functions hyperlinks perform in news stories. Previous research, as well as my previous examination of meta-journalistic discourses, has shown that one of the alleged functions of links is to display the writer's sources. In that sense, hyperlinks are “journalistic objects of evidence” as they can directly point to the documents, data or discourses used as rough material for a news story. The present paper puts that particular function of hyperlinks to the test. It conducts a content analysis on a sub-sample of the stories published on six Belgian news sites that contain at least one external link, and compares the links with the sources explicitly mentioned in the news story itself. Results highlight that links and the mentions of sources do not overlap completely. Many sources are not reflected in links, and most links do not point to primary sources per se. Other functions of links emerge, such as providing a service or contextual information to the readers. These findings thus question the material nature of “journalistic objects of evidence” and the possibility for journalists to build networks of distributed responsibility with links.  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