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   4771篇
  免费   53篇
  国内免费   10篇
教育   3547篇
科学研究   278篇
各国文化   43篇
体育   423篇
综合类   3篇
文化理论   65篇
信息传播   475篇
  2022年   33篇
  2021年   55篇
  2020年   65篇
  2019年   124篇
  2018年   149篇
  2017年   161篇
  2016年   158篇
  2015年   107篇
  2014年   125篇
  2013年   975篇
  2012年   137篇
  2011年   133篇
  2010年   152篇
  2009年   142篇
  2008年   150篇
  2007年   146篇
  2006年   114篇
  2005年   101篇
  2004年   104篇
  2003年   89篇
  2002年   96篇
  2001年   69篇
  2000年   109篇
  1999年   75篇
  1998年   76篇
  1997年   63篇
  1996年   73篇
  1995年   57篇
  1994年   67篇
  1993年   64篇
  1992年   52篇
  1991年   71篇
  1990年   51篇
  1989年   47篇
  1988年   38篇
  1987年   46篇
  1986年   45篇
  1985年   44篇
  1984年   48篇
  1983年   39篇
  1982年   31篇
  1981年   37篇
  1980年   30篇
  1979年   26篇
  1978年   33篇
  1977年   39篇
  1976年   28篇
  1975年   22篇
  1974年   23篇
  1972年   16篇
排序方式: 共有4834条查询结果,搜索用时 15 毫秒
101.
Objectives: To improve well-being and performance indicators in a group of Australian Football League (AFL) players via a six-week sleep optimisation programme. Design: Prospective intervention study following observations suggestive of reduced sleep and excessive daytime sleepiness in an AFL group. Methods: Athletes from the Adelaide Football Club were invited to participate if they had played AFL senior-level football for 1–5 years, or if they had excessive daytime sleepiness (Epworth Sleepiness Scale [ESS] >10), measured via ESS. An initial education session explained normal sleep needs, and how to achieve increased sleep duration and quality. Participants (n?=?25) received ongoing feedback on their sleep, and a mid-programme education and feedback session. Sleep duration, quality and related outcomes were measured during week one and at the conclusion of the six-week intervention period using sleep diaries, actigraphy, ESS, Pittsburgh Sleep Quality Index, Profile of Mood States, Training Distress Scale, Perceived Stress Scale and the Psychomotor Vigilance Task. Results: Sleep diaries demonstrated an increase in total sleep time of approximately 20?min (498.8?±?53.8 to 518.7?±?34.3; p?<?.05) and a 2% increase in sleep efficiency (p?<?0.05). There was a corresponding increase in vigour (p?<?0.001) and decrease in fatigue (p?<?0.05). Conclusions: Improvements in measures of sleep efficiency, fatigue and vigour indicate that a sleep optimisation programme may improve athletes’ well-being. More research is required into the effects of sleep optimisation on athletic performance.  相似文献   
102.
With reference to the recent science studies debate on the nature of science-industry relationship, this article focuses on a novel organizational form: the technological platform. Considering the field of micro- and nanotechnology in Switzerland, it investigates how technological platforms participate in framing science-industry activities. On the basis of a comparative analysis of three technological platforms, it shows that the platforms relate distinctly to academic and to industrial users. It distinguishes three pairs of user models, one model in each pair pertaining to how platforms act toward and conceive of academic users, the other model regarding users from industry. The article then discusses how technological platforms reconfigure the science-economy divide. While the observed platforms provide new institutional contact and interaction between academia and industry, new research collaboration does not necessarily materialize in practice. In this respect, science-industry mediation by way of technological platforms does not make science-industry boundaries more porous. Instead, the declared openness of public research with respect to industry, in the case of technological platforms, may contribute to maintain public science’s autonomy.  相似文献   
103.
104.
The authors replicated a study (White, 1979) in which high correlations were obtained among the Wechsler Intelligence Scale for Children-Revised (WISC-R), the Peabody Individual Achievement Test (PIAT), and the Goodenough-Harris Draw-A-Man (DAM), and conclusions were drawn that all these instruments might not be necessary in the same test battery. The present study involved a larger sample (360 children). Much lower correlations among the instruments were obtained, although the pattern of correlation was similar. It was concluded that results of the White study may have overestimated the relationships between the variables because of factors unique to the sample. Test specificity appeared using the larger, normally distributed sample, suggesting a legitimate use of all three tests in a single battery.  相似文献   
105.
106.
Evidence of the internal consistency of standard-setting judgments is a critical part of the validity argument for tests used to make classification decisions. The bookmark standard-setting procedure is a popular approach to establishing performance standards, but there is relatively little research that reflects on the internal consistency of the resulting judgments. This article presents the results of an experiment in which content experts were randomly assigned to one of two response probability conditions: .67 and .80. If the standard-setting judgments collected with the bookmark procedure are internally consistent, both conditions should produce highly similar cut scores. The results showed substantially different cut scores for the two conditions; this calls into question whether content experts can produce the type of internally consistent judgments that are required using the bookmark procedure.  相似文献   
107.
108.
ABSTRACT

To maintain the accuracy of squash shots under varying conditions, such as the oncoming ball’s velocity and trajectory, players must adjust their technique. Although differences in technique between skilled and less-skilled players have been studied, it is not yet understood how players vary their technique in a functional manner to maintain accuracy under varying conditions. This study compared 3-dimensional joint and racket kinematics and their variability between accurate and inaccurate squash forehand drives of 9 highly skilled and 9 less-skilled male athletes. During inaccurate shots, less-skilled players hit the ball with a more open racket, demonstrating a difference in this task-relevant parameter. No joint kinematic differences were found for accuracy for either group. Coordinated joint rotations at the elbow and wrist both displayed a “zeroing-in” effect, whereby movement variability was reduced from the initiation of propulsive joint rotation to a higher consistency at ball-impact; potentially highlighting the “functionality” of the variability prior to the impact that enabled consistent task-relevant parameters (racket orientation and velocity) under varying conditions. Further, highly skilled players demonstrated greater consistency of task-relevant parameters at impact than less-skilled players. These findings highlight the superior ability of highly skilled players to adjust their technique to achieve consistent task-relevant parameters and a successful shot.  相似文献   
109.
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   
110.
The primary roles for nutrition in sprints are for recovery from training and competition and influencing training adaptations. Sprint success is determined largely by the power-to-mass ratio, so sprinters aim to increase muscle mass and power. However, extra mass that does not increase power may be detrimental. Energy and protein intake are important for increasing muscle mass. If energy balance is maintained, increased mass and strength are possible on a wide range of protein intakes, so energy intake is crucial. Most sprinters likely consume ample protein. The quantity of energy and protein intake necessary for optimal training adaptations depends on the individual athlete and training demands; specific recommendations for all sprinters are, at best, useless, and are potentially harmful. However, if carbohydrate and fat intake are sufficient to maintain energy levels, then increased protein intake is unlikely to be detrimental. The type and timing of protein intake and nutrients ingested concurrently must be considered when designing optimal nutritional strategies for increasing muscle mass and power. On race day, athletes should avoid foods that result in gastrointestinal discomfort, dehydration or sluggishness. Several supplements potentially influence sprint training or performance. Beta-alanine and bicarbonate may be useful as buffering agents in longer sprints. Creatine may be efficacious for increasing muscle mass and strength and perhaps increasing intensity of repeat sprint performance during training.  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