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   3594篇
  免费   73篇
教育   2733篇
科学研究   139篇
各国文化   21篇
体育   474篇
综合类   1篇
文化理论   82篇
信息传播   217篇
  2023年   33篇
  2022年   55篇
  2021年   69篇
  2020年   114篇
  2019年   221篇
  2018年   305篇
  2017年   262篇
  2016年   253篇
  2015年   140篇
  2014年   174篇
  2013年   716篇
  2012年   124篇
  2011年   78篇
  2010年   113篇
  2009年   76篇
  2008年   79篇
  2007年   67篇
  2006年   72篇
  2005年   45篇
  2004年   46篇
  2003年   50篇
  2002年   33篇
  2001年   40篇
  2000年   35篇
  1999年   26篇
  1998年   26篇
  1997年   23篇
  1996年   24篇
  1995年   28篇
  1994年   23篇
  1993年   18篇
  1992年   17篇
  1991年   9篇
  1990年   12篇
  1989年   17篇
  1988年   13篇
  1987年   11篇
  1986年   7篇
  1985年   18篇
  1984年   13篇
  1982年   12篇
  1981年   10篇
  1980年   9篇
  1979年   10篇
  1978年   12篇
  1974年   13篇
  1973年   13篇
  1972年   13篇
  1957年   7篇
  1956年   7篇
排序方式: 共有3667条查询结果,搜索用时 15 毫秒
1.
Learners who enrol in massive open online courses (MOOCs) have different backgrounds and tend to have different motivations than learners in traditional courses. Based on value-expectancy theory, an instrument was developed to measure motivation for enrolling in a programming MOOC. A study with 1229 adult participants in Estonian-language programming course “About Programming” was conducted to validate the instrument. Results of confirmatory factor analysis validated the 7-factor scale named factors influencing enrolment in MOOC (FIEM). FIEM comprises three factors of expectancies, three factors of values and one factor of social influence. The highest and lowest rated motivational factors influencing enrolment in programming MOOC are discussed in the paper. Interest in and expectations for the course, personal suitability of distance learning and suitability for family and work are the highest-rated motivational factors for those who enrol in MOOC. Usefulness related to own children, social influence and usefulness to related to certification were the lowest rated. The results of this study can be useful for designers of programming MOOCs and the developed scale might be used in future studies.  相似文献   
2.
3.
4.
5.
The aim of the present study was to examine the movement patterns, ball skills, and the impressions of Swedish elite football players during competitive games on artificial turf and natural grass. Time - motion analyses (36 observations) and technical analyses (16 team observations) were performed and 72 male and 21 female players completed a questionnaire. No differences were observed between artificial turf and natural grass in terms of total distance covered (mean 10.19 km, s = 0.19 vs. 10.33 km, s = 0.23), high-intensity running (1.86 km, s = 0.10 vs. 1.87 km, s = 0.14), number of sprints (21, s = 1 vs. 22, s = 2), standing tackles (10, s = 1 vs. 11, s = 1) or headers per game (8, s = 1 vs. 8, s = 1), whereas there were fewer sliding tackles (P < 0.05) on artificial turf than natural grass (2.1, s = 0.5 vs. 4.3, s = 0.6). There were more short passes (218, s = 14 vs. 167, s = 12) and midfield-to-midfield passes (148, s = 11 vs. 107, s = 8) (both P < 0.05) on artificial turf than natural grass. On a scale of 0-10, where 0 = "better than", 5 = "equal to", and 10 = "worse than", the male players reported a negative overall impression (8.3, s = 0.2), poorer ball control (7.3, s = 0.3), and greater physical effort (7.2, s = 0.2) on artificial turf than natural grass. In conclusion, the running activities and technical standard were similar during games on artificial turf and natural grass. However, fewer sliding tackles and more short passes were performed during games on artificial turf. The observed change in playing style could partly explain the male players' negative impression of artificial turf.  相似文献   
6.
7.
György Péteri 《Minerva》1996,34(4):367-380
Conclusions On the basis of these findings, I suggest that the structure and organisation of the field of Hungarian economics under state socialism should be described as a case of partitioned bureaucracy.9 The compromise between research economists and the political elite in the New Course era between 1953 and 195510 survived the post-1956 reaction in so far as political economy, with its predominantly legitimatory and ideological functions, remained partitioned from the other sectors in the field through the remainder of the state-socialist period. This secured considerable protection both for Marxist-Leninist political economy—which faced the destabilising effects of exposure to the findings of serious empirical research—and for the other sectors, which were professionally oriented and earnestly interested in the pursuit of unbiased empirical research, free from stifling agitprop interference. Our data concerning the reputational control of the field reflects only one, although very important, aspect of this partitioning. Another and much plainer aspect is that, from the early 1960s, the Agitation and Propaganda Department of the Central Committee no longer exercised control over the field, except in the political economy sector.The proposition about the mechanism paradigm should not be taken seriously as a statement of a Kuhnian type of intellectual organisation of Hungarian economics, with reform economics at its hard theoretical core. But it should certainly be taken seriously as a reflection of the sociopolitical structure which emerged and developed from the mid-1950s onwards. Neither the politicians nor the economists saw as necessary or even contemplated the integration of Hungarian economic research with Western mainstream economic thought. In exchange for the professional expertise and socio-economic intelligence necessary for the exercise of power, Hungary's state-socialist political class offered their economists relative autonomy and freedom from interference. The price the economists had to pay was partly to refrain from openly and systematically challenging the beliefs perpetuated by the political economy of socialism, and partly to accept in their research the paramountcy of policy orientation. But this burden they assumed willingly since it made them the only group within Hungary's academic intelligentsia—indeed, the only group in Hungarian society outside the political class—with the privilege of being coopted to the institutions with power over some restricted domains of policymaking. After 1989, especially under the conservative Antall government, this proved less than advantageous.11 Although the benevolence of many critics is open to question, it could greatly benefit the field if the economists' expulsion from contemporary politics went hand in hand with provision of the material, intellectual and institutional conditions for a new approach where a fundamentally scientific orientation is paramount.  相似文献   
8.
9.
10.
Search facilitated with agglomerative hierarchical clustering methods was studied in a collection of Finnish newspaper articles (N = 53,893). To allow quick experiments, clustering was applied to a sample (N = 5,000) that was reduced with principal components analysis. The dendrograms were heuristically cut to find an optimal partition, whose clusters were compared with each of the 30 queries to retrieve the best-matching cluster. The four-level relevance assessment was collapsed into a binary one by (A) considering all the relevant and (B) only the highly relevant documents relevant, respectively. Single linkage (SL) was the worst method. It created many tiny clusters, and, consequently, searches enabled with it had high precision and low recall. The complete linkage (CL), average linkage (AL), and Ward's methods (WM) returned reasonably-sized clusters typically of 18–32 documents. Their recall (A: 27–52%, B: 50–82%) and precision (A: 83–90%, B: 18–21%) was higher than and comparable to those of the SL clusters, respectively. The AL and WM clustering had 1–8% better effectiveness than nearest neighbor searching (NN), and SL and CL were 1–9% less efficient that NN. However, the differences were statistically insignificant. When evaluated with the liberal assessment A, the results suggest that the AL and WM clustering offer better retrieval ability than NN. Assessment B renders the AL and WM clustering better than NN, when recall is considered more important than precision. The results imply that collections in the highly inflectional and agglutinative languages, such as Finnish, may be clustered as the collections in English, provided that documents are appropriately preprocessed.  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