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   120257篇
  免费   1886篇
  国内免费   245篇
教育   82917篇
科学研究   13431篇
各国文化   2043篇
体育   9479篇
综合类   182篇
文化理论   1140篇
信息传播   13196篇
  2021年   958篇
  2020年   1692篇
  2019年   2624篇
  2018年   3141篇
  2017年   3446篇
  2016年   3477篇
  2015年   2378篇
  2014年   3246篇
  2013年   27706篇
  2012年   2450篇
  2011年   2816篇
  2010年   2401篇
  2009年   2682篇
  2008年   2480篇
  2007年   2198篇
  2006年   2433篇
  2005年   2433篇
  2004年   3100篇
  2003年   2406篇
  2002年   2221篇
  2001年   2045篇
  2000年   1725篇
  1999年   1589篇
  1998年   1382篇
  1997年   1377篇
  1996年   1581篇
  1995年   1378篇
  1994年   1368篇
  1993年   1362篇
  1992年   1370篇
  1991年   1268篇
  1990年   1288篇
  1989年   1195篇
  1988年   1042篇
  1987年   1008篇
  1986年   1019篇
  1985年   1266篇
  1984年   1177篇
  1983年   1091篇
  1982年   1082篇
  1981年   1015篇
  1980年   962篇
  1979年   1077篇
  1978年   1061篇
  1977年   963篇
  1976年   875篇
  1975年   701篇
  1974年   700篇
  1973年   665篇
  1972年   517篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
Dropping out of university is regularly discussed as a negative indicator. However, research on actual career trajectories of dropouts is virtually non‐existent. This study estimates the association between tertiary dropouts and career chances in 15 European countries. Using data from the 2011 Programme for the International Assessment of Adult Competencies (PIAAC), estimates are derived from the application of propensity score matching taking a variety of individual background characteristics including cognitive skills into account. Results indicate that individuals are likely to fare better in the labour market if they enrol in university and drop out than if they do not enrol at all. Policy makers need to revise the notion that dropping out is purely negative.  相似文献   
993.
ABSTRACT

North Carolina Central University (NCCU) recognized the need to address the increasing rates of Ds, Fs, and Withdrawal by students matriculating in online courses. Led by two science faculty, a faculty learning community in partnership with the NCCU Division of Extended Studies was created to assess online science course offerings and instruction. Faculty within this learning community completed the Quality Matters (QM) “Applying the Quality Matters Rubric” course. This online training course, coupled with services provided by the NCCU Division of Extended Studies, offered the faculty learning community a variety of pedagogical strategies to meet their instructional needs. All faculty participating in this learning community completed the online training course and all faculty indicated that they implemented changes in their subsequent online course offerings. This article describes the impact of that training and the application of quality course design standards in the Quality Matters Rubric on the design and student outcomes for an Introductory Biology course over four terms. As faculty learning communities are broadly utilized, it is anticipated that this article may present an effective strategy to increase the quality and quantity of online science, technology, engineering and mathematics (STEM) courses at similar institutions.  相似文献   
994.
995.
‘A tribute to Dr J. Rogge’ aims to systematically review muscle activity and muscle fatigue during sustained submaximal quasi-isometric knee extension exercise (hiking) related to Olympic dinghy sailing as a tribute to Dr Rogge’s merits in the world of sports. Dr Jacques Rogge is not only the former President of the International Olympic Committee, he was also an orthopaedic surgeon and a keen sailor, competing at three Olympic Games. In 1972, in fulfilment of the requirements for the degree of Master in Sports Medicine, he was the first who studied a sailors’ muscle activity by means of invasive needle electromyography (EMG) during a specific sailing technique (hiking) on a self-constructed sailing ergometer. Hiking is a bilateral and multi-joint submaximal quasi-isometric movement which dinghy sailors use to optimize boat speed and to prevent the boat from capsizing. Large stresses are generated in the anterior muscles that cross the knee and hip joint, mainly employing the quadriceps at an intensity of 30–40% maximal voluntary contraction (MVC), sometimes exceeding 100% MVC. Better sailing level is partially determined by a lower rate of neuromuscular fatigue during hiking and for ≈60% predicted by a higher maximal isometric quadriceps strength. Although useful in exercise testing, prediction of hiking endurance capacity based on the changes in surface EMG in thigh and trunk muscles during a hiking maintenance task is not reliable. This could probably be explained by the varying exercise intensity and joint angles, and the great number of muscles and joints involved in hiking.

Highlights

  • Dr Jacques Rogge, former president of the International Olympic Committee and Olympic Finn sailor, was the first to study muscle activity during sailing using invasive needle EMG to obtain his Master degree in Sports Medicine at the Ghent University.

  • Hiking is a critical bilateral and multi-joint movement during dinghy racing, accounting for >60% of the total upwind leg time. Hiking generates large stresses in the anterior muscles that cross the knee and hip joint.

  • Hiking is considered as a quasi-isometric bilateral knee extension exercise. Muscle activity measurements during sailing, recorded by means of EMG, show a mean contraction intensity of 30-40% maximal voluntary contraction with peaks exceeding 100%.

  • Hiking performance is strongly related to the development of neuromuscular fatigue in the quadriceps muscle. Since maximal strength is an important determinant of neuromuscular fatigue during hiking, combined strength and endurance training should be incorporated in the training program of dinghy sailors.

  相似文献   
996.
Background: Motor skill (MS) competence is an important contributing factor for healthy development.

Purpose: The goal was to test the effectiveness of primary school physical education (PE) on MS and physical fitness (PF) development.

Methods: Three classes (n?=?60, aged 9.0?±?0.9) were randomly assigned to three diverse conditions during a school year: two PE lessons/week (PE-2), three PE lessons/week (PE-3), and no PE lessons control group (CG). BMI, skinfolds, PF (9-min run/walk, sit-up, modified pull-ups), gymnastics, soccer, handball, basketball and track-and-field skills were evaluated. Effect sizes (d) were reported as magnitude of change.

Results: Skinfolds significantly increased only in CG (d?=?1.21). PF composite z-scores improved in PE-3 (d?=?0.61), but decreased in PE-2 (d?=?0.57), and had no changes in CG. Statistically significant improvement was verified in gymnastics and handball skills in both experimental groups (gymnastic: d?=?2.95 and d?=?2.61 for PE-3 and PE-2, respectively; handball: d?=?1.87 and d?=?0.57 for PE-3 and PE-2, respectively), and no changes were seen in CG. In soccer, there were improvements only in the PE-3 (d?=?0.55), and in basketball only in PE-2 (d?=?0.46). There were no changes in any group for track-and-field skills.

Conclusions: PE programs can effectively promote PF and MS development.  相似文献   
997.
998.
This article focuses on the Soviet sports agency Sovintersport, which was created in the late 1980s and became an import–export company for everything related to sport in the Soviet Union. Sovintersport and its subsidiary companies were responsible for importing and exporting sporting equipment, negotiating sponsorship contracts with foreign companies, as well as the transferring of Soviet athletes and coaches to other countries. This article will, therefore, analyse the operations of Sovintersport and its subsidiary companies in the period between 1987 and 1991, with a special focus on foot-ball related operations. Sovintersport is in many ways is an excellent case study, which illustrates how international trading corporations that were set up during Gorbachev’s reign of the Soviet Union, operated. Sovintersport demonstrates how football in the Soviet Union turned from a spectator sport into a valuable asset that was worth capitalizing on.  相似文献   
999.
Abstract

Quiet eye training (QET) may be a more effective method for teaching children to catch than traditional training (TT) methods, but it is unclear if the benefits accrued persist in the long term. Thirty children were randomly allocated into a QET or TT group and, while wearing a mobile eye tracker, underwent baseline testing, training and two retention tests over a period of eight weeks, using a validated throw and catch task. During training, movement-related information was provided to both groups, while the QET group received additional instruction to increase the duration of their targeting fixation (QE1) on the wall prior to the throw, and pursuit tracking (QE2) period on the ball prior to catching. In both immediate (R1) and delayed (R2, six weeks later) retention tests, the QET group had a significantly longer QE1 duration and an earlier and longer QE2 duration, compared to the TT group, who revealed no improvements. A performance advantage was also found for the QET compared to the TT group at both R1 and R2, revealing the relatively robust nature of the visuomotor alterations. Regression analyses suggested that only the duration of QE1 predicted variance in catch success post-training, pointing to the importance of a pre-programming visuomotor strategy for successful throw and catch performance.  相似文献   
1000.
The present study aimed to examine whether physical and environment elements of PETTLEP imagery relate to the ability to image five types of sport imagery (i.e. skill, strategy, goal, affect and mastery). Two hundred and ninety participants (152 males, 148 females; Mage?=?20.24 years, SD?=?4.36) from various sports completed the Sport Imagery Ability Questionnaire (SIAQ), and a set of items designed specifically for the study to assess how frequently participants incorporate physical (e.g. ‘I make small movements or gestures during the imagery’) and environment (e.g. ‘I image in the real training/competition environment’) elements of PETTLEP imagery. Structural equation modelling tested a hypothesised model in which imagery priming (i.e. the best fitting physical and environment elements) significantly and positively predicted imagery ability of the different imagery types (skill, β?=?0.38; strategy, β?=?0.23; goal, β?=?0.21; affect, β?=?0.25; mastery, β?=?0.22). The model was a good fit to the data: χ2 (174)?=?263.87, p?<?.001, CFI?=?.96, TLI?=?.95, SRMR?=?.09, RMSEA?=?0.05 (90% CI?=?0.03–0.05). Findings displayed that priming imagery with physical and environment elements is associated with better skill, strategy, goal, affect and mastery imagery ability. The findings extend models of imagery use by indicating that how athletes images may influence their imagery ability.  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