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   590篇
  免费   21篇
教育   369篇
科学研究   63篇
各国文化   8篇
体育   105篇
综合类   1篇
文化理论   11篇
信息传播   54篇
  2023年   3篇
  2022年   11篇
  2021年   17篇
  2020年   25篇
  2019年   34篇
  2018年   54篇
  2017年   49篇
  2016年   46篇
  2015年   22篇
  2014年   21篇
  2013年   108篇
  2012年   28篇
  2011年   21篇
  2010年   19篇
  2009年   15篇
  2008年   28篇
  2007年   16篇
  2006年   8篇
  2005年   16篇
  2004年   11篇
  2003年   6篇
  2002年   5篇
  2001年   3篇
  2000年   5篇
  1999年   1篇
  1998年   3篇
  1997年   3篇
  1995年   1篇
  1994年   2篇
  1993年   2篇
  1991年   1篇
  1990年   2篇
  1989年   1篇
  1988年   4篇
  1985年   2篇
  1984年   1篇
  1983年   1篇
  1982年   2篇
  1981年   3篇
  1979年   2篇
  1978年   2篇
  1976年   1篇
  1974年   1篇
  1973年   2篇
  1972年   2篇
  1903年   1篇
排序方式: 共有611条查询结果,搜索用时 0 毫秒
571.
The aim was to explore how young riders experience the riding school. By analysing focus groups interviews, a picture emerged showing that young riders’ main motive for participating at riding schools was the social aspects. Riding schools could be characterized through an institutional perspective in which the young riders became internalized and socialized into a stable culture. The young riders identified with the norms and values of the riding instructors through master–apprentice learning. In addition, the results revealed a change in the stable culture since the instructors encouraged social interactions and participation in the community that became central to learning and development. Opportunities to influence and interact were important for the individuals and from a child’s rights perspective. Through participation in the community of practice at riding schools, young riders not only learn about riding and horse management but also develop important personal social skills.  相似文献   
572.
A tube-in-square-pipe microfluidic glass cell has been developed for studying the aggregation and fiber formation from regenerated silk solution by in-situ small-angle X-ray scattering using synchrotron radiation. Acidification-induced aggregation has been observed close to the mixing point of the fibroin and buffer solution. The fibrous, amorphous material is collected in a water bath. Micro-wide-angle X-ray scattering of the dried material confirms its β-sheet nature.  相似文献   
573.
We consider the following autocompletion search scenario: imagine a user of a search engine typing a query; then with every keystroke display those completions of the last query word that would lead to the best hits, and also display the best such hits. The following problem is at the core of this feature: for a fixed document collection, given a set D of documents, and an alphabetical range W of words, compute the set of all word-in-document pairs (w, d) from the collection such that w W and d ∈ D. We present a new data structure with the help of which such autocompletion queries can be processed, on the average, in time linear in the input plus output size, independent of the size of the underlying document collection. At the same time, our data structure uses no more space than an inverted index. Actual query processing times on a large test collection correlate almost perfectly with our theoretical bound.
Ingmar WeberEmail:
  相似文献   
574.
Creating public value is a key goal of public administrations, both in their daily business and in the growing field of smart government and smart cities, which focuses on IT-enabled innovations in the public sphere. However, many public administrations still struggle with such innovations due to complex technologies, high investments, and the numerous stakeholders involved. To address this issue, some local governments in continental Europe have turned to collaborative innovation approaches, partnering with (semi-)public utility companies in the hope that their additional innovation assets will boost innovativeness. Nevertheless, it remains unclear how exactly such collaborations should be governed to ensure that the focus remains on creating public value, as utility companies may have their own agendas. To explore this question, we conducted a comparative case study in the context of smart city initiatives with four cases in Swiss local governments. Drawing on agency and stewardship theory, we then propose a model of public-value-focused collaborative innovation, enabling us to explore various collaboration characteristics and their effects on public value creation. Our findings suggest that both agency- and stewardship-based collaborations increase innovativeness. However, while agency collaborations tend to produce smart city innovations that mainly serve the utility companies' business interests, stewardship relationships lead to innovations that are focused more on public value creation. As such, our study extends the literature on the effects of collaborative innovation on public value, and it provides practical recommendations on how such collaborative innovation should be designed.  相似文献   
575.
The purpose of this study was to determine the physiological, anthropometric, performance, and nutritional characteristics of the Brazil Canoe Polo National Team. Ten male canoe polo athletes (age 26.7 ± 4.1 years) performed a battery of tests including assessments of anthropometric parameters, upper-body anaerobic power (Wingate), muscular strength, aerobic power, and nutritional profile. In addition, we characterized heart rate and plasma lactate responses and the temporal pattern of the effort/recovery during a simulated canoe polo match. The main results are as follows: body fat, 12.3 ± 4.0%; upper-body peak and mean power, 6.8 ± 0.5 and 4.7 ± 0.4 W · kg(-1), respectively; 1-RM bench press, 99.1 ± 11.7 kg; peak oxygen uptake, 44.3 ± 5.8 mL · kg(-1) · min(-1); total energy intake, 42.8 ± 8.6 kcal · kg(-1); protein, carbohydrate, and fat intakes, 1.9 ± 0.1, 5.0 ± 1.5, and 1.7 ± 0.4 g · kg(-1), respectively; mean heart rate, 146 ± 11 beats · min(-1); plasma lactate, 5.7 ± 3.8 mmol · L(-1) at half-time and 4.6 ± 2.2 mmol · L(-1) at the end of the match; effort time (relative to total match time), 93.1 ± 3.0%; number of sprints, 9.6 ± 4.4. The results of this study will assist coaches, trainers, and nutritionists in developing more adequate training programmes and dietary interventions for canoe polo athletes.  相似文献   
576.
Background: Although accumulating evidence suggests that motor and cognitive development is interrelated, only a few studies have investigated links between executive function and motor control. Therefore, the present cross-sectional study examined the relationship between motor competences and core components of executive functioning, including inhibitory control, working memory and cognitive flexibility. Methods: In 89 preadolescent children, motor competences were assessed using the MOBAK-5 test battery. Additionally, all participants completed computer-based versions of the Flanker task, which included standard and switch blocks, and the 2-Back task. Results: Partial correlations (correcting for age, gender and body mass index) revealed that locomotor skills were associated with the adjusted hit-rate on the 2-Back task (r?=?0.34) whereas object control was linked with conflict score on the Flanker task (r?=??0.39). In contrast, there was no correlation between switch costs and motor competences. Conclusion: In preadolescent children, high competences in locomotor skills and object control skills are associated with high performance on specific executive function tasks. This finding supports the current view that motor competences and cognitive control share some common underlying processes.  相似文献   
577.
Abstract

Few studies have focused on the effect of posture during sprint start. The aim of this study was to measure the effect of the modification of horizontal distance between the blocks during sprint start on three dimensional (3D) joint angular velocity. Nine trained sprinters started using three different starting positions (bunched, medium and elongated). They were equipped with 63 passive reflective markers, and an opto-electronic Motion Analysis® system was used to collect the 3D marker trajectories. During the pushing phase on the blocks, norm of the joint angular velocity (NJAV), 3D Euler angular velocity (EAV) and pushing time on the blocks were calculated. The results demonstrated that the decrease of the block spacing induces an opposite effect on the angular velocity of joints of the lower and the upper limbs. The NJAV of the upper limbs is greater in the bunched start, whereas the NJAV of the lower limbs is smaller. The modifications of NJAV were due to a combination of the movement of the joints in the different degrees of freedom. The medium start seems to be the best compromise because it leads, in a short pushing time, to a combination of optimal joint velocities for upper and lower segments.  相似文献   
578.
Zun?chst wird über die INterpretation eines antiken Reliefs, der so genannten „sinnenden Athena“, ein Zugang zur Bildungskonfiguration in der klassischen griechischen Antike gesucht. An diesem Beispiel einer historischen Rekonstruktion werden dann fünf Merkmale herausgearbeitet, die hermeneutische Forschung in der P?dagogik kennzeichnen: 1. szientistische Verfahren, 2. Kulturanalysen, 3. ein Methodenverst7;andnis des Anteilnehmens am Forschungsgegenstand, 4. Vertrautsein mit dem Forschungsfeld und 5. Ideologiekrritik.  相似文献   
579.
This study examined whether having vulnerable friends helps or hurts victimized and depressed (i.e., vulnerable) adolescents and whether this depends on classroom supportive norms. Students (n = 1461, 46.7% girls, 93.4% Han nationality) were surveyed four times from seventh and eighth grade (Mage = 13 years) in 2015 and 2016 in Central China. Longitudinal social network analyses indicated that having vulnerable friends can both hurt and help vulnerable adolescents. Depressed adolescents with depressed friends increased in victimization over time. Victimized adolescents with victimized friends increased in victimization but decreased in depressive symptoms. These processes were most likely in classrooms with high supportive norms. Having friends and a supportive classroom may hurt vulnerable adolescents' social position but help victims' emotional development.  相似文献   
580.
Perfused three-dimensional (3D) cultures enable long-term in situ growth and monitoring of 3D organoids making them well-suited for investigating organoid development, growth, and function. One of the limitations of this long-term on-chip perfused 3D culture is unintended and disruptive air bubbles. To overcome this obstacle, we invented an imaging platform that integrates an innovative microfluidic bubble pocket for long-term perfused 3D culture of gastrointestinal (GI) organoids. We successfully applied 3D printing technology to create polymer molds that cast polydimethylsiloxane (PDMS) culture chambers in addition to bubble pockets. Our developed platform traps unintended, or induced, air bubbles in an integrated PDMS pocket chamber, where the bubbles diffuse out across the gas permeable PDMS or an outlet tube. We demonstrated that our robust platform integrated with the novel bubble pocket effectively circumvents the development of bubbles into human and mouse GI organoid cultures during long-term perfused time-course imaging. Our platform with the innovative integrated bubble pocket is ideally suited for studies requiring long-term perfusion monitoring of organ growth and morphogenesis as well as function.  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