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   4847篇
  免费   59篇
  国内免费   10篇
教育   3496篇
科学研究   411篇
各国文化   102篇
体育   397篇
综合类   1篇
文化理论   49篇
信息传播   460篇
  2021年   39篇
  2020年   60篇
  2019年   111篇
  2018年   132篇
  2017年   136篇
  2016年   160篇
  2015年   99篇
  2014年   113篇
  2013年   1244篇
  2012年   92篇
  2011年   112篇
  2010年   102篇
  2009年   109篇
  2008年   125篇
  2007年   98篇
  2006年   84篇
  2005年   103篇
  2004年   97篇
  2003年   82篇
  2002年   101篇
  2001年   72篇
  2000年   73篇
  1999年   77篇
  1998年   46篇
  1997年   56篇
  1996年   45篇
  1995年   52篇
  1994年   44篇
  1993年   40篇
  1992年   53篇
  1991年   67篇
  1990年   56篇
  1989年   50篇
  1988年   34篇
  1987年   54篇
  1986年   37篇
  1985年   54篇
  1984年   50篇
  1983年   48篇
  1982年   37篇
  1981年   37篇
  1980年   26篇
  1979年   40篇
  1978年   47篇
  1977年   41篇
  1976年   29篇
  1975年   34篇
  1974年   23篇
  1973年   21篇
  1971年   26篇
排序方式: 共有4916条查询结果,搜索用时 62 毫秒
21.
Research suggests that spatial ability may predict success in complex disciplines including anatomy, where mastery requires a firm understanding of the intricate relationships occurring along the course of veins, arteries, and nerves, as they traverse through and around bones, muscles, and organs. Debate exists on the malleability of spatial ability, and some suggest that spatial ability can be enhanced through training. It is hypothesized that spatial ability can be trained in low-performing individuals through visual guidance. To address this, training was completed through a visual guidance protocol. This protocol was based on eye-movement patterns of high-performing individuals, collected via eye-tracking as they completed an Electronic Mental Rotations Test (EMRT). The effects of guidance were evaluated using 33 individuals with low mental rotation ability, in a counterbalanced crossover design. Individuals were placed in one of two treatment groups (late or early guidance) and completed both a guided, and an unguided EMRT. A third group (no guidance/control) completed two unguided EMRTs. All groups demonstrated an increase in EMRT scores on their second test (P < 0.001); however, an interaction was observed between treatment and test iteration (P = 0.024). The effect of guidance on scores was contingent on when the guidance was applied. When guidance was applied early, scores were significantly greater than expected (P = 0.028). These findings suggest that by guiding individuals with low mental rotation ability “where” to look early in training, better search approaches may be adopted, yielding improvements in spatial reasoning scores. It is proposed that visual guidance may be applied in spatial fields, such as STEMM (science, technology, engineering, mathematics and medicine), surgery, and anatomy to improve student's interpretation of visual content. Anat Sci Educ. © 2018 American Association of Anatomists.  相似文献   
22.
James Davies 《Metascience》2015,24(3):483-486
  相似文献   
23.
ABSTRACT

This study aimed to assess the effect of playing surface (Natural [NT] and Artificial [AT] Turf) on the fatigue response to a soccer-specific exercise protocol (SSEP). Eighteen male soccer players completed the SSEP on NT and AT with pre-, post-, and 48 h post-assessments of eccentric knee flexor (eccKF) and concentric knee extensor peak torque (PT), peak countermovement (CMJ) and squat jump (SJ) height, and Nordic hamstring break angle. No significant main effects for surface or any surface and time interactions were observed for any of the outcome measures, except for eccKF PT recorded at 3.14 rad·s-1, which was significantly lower 48 h post-trial in the AT condition (AT = 146.3 ± 20.4 Nm; NT = 158.8 ± 24.7 Nm). Main effects for time were observed between pre- and post-trial measures for eccKF PT at all angular velocities, Nordic break angle, CMJ and SJ height. Nordic break angle, and both CMJ and SJ height were significantly impaired 48 h post-trial when compared to pre-trial. The findings of the current study suggest surface dependent changes in eccKF PT which may have implications for recovery and subsequent performance after competition on AT.  相似文献   
24.
25.
26.
The purpose of this study was to compare arm–leg coordination and kinematics during 100 m breaststroke in 26 (8 female; 18 male) specialist breaststroke swimmers. Laps were recorded using three 50-Hz underwater cameras. Heart rate and blood lactate were measured pre- and post-swim. Arm–leg coordination was defined using coordination phases describing continuity between recovery and propulsive phases of upper and lower limbs: coordination phase 1 (time between end of leg kick and start of the arm pull phases); and coordination phase 2 (time between end of arm pull and start of leg kick phases). Duration of stroke phases, coordination phases, swim velocity, stroke length (SL), stroke rate (SR) and stroke index (SI) were analysed during the last three strokes of each lap that were unaffected by turning or finishing. Significant changes in velocity, SI and SL (P < 0.05) were found between laps. Both sexes showed significant increase (P < 0.05) in heart rate and blood lactate pre- to post-swim. Males had significantly (P < 0.01) faster swim velocities resulting from longer SLs (P = 0.016) with no difference in SR (P = 0.064). Sex differences in kinematic parameters can be explained by anthropometric differences providing males with increased propelling efficiency.  相似文献   
27.
This study investigated the extent to which position in the Australian Football League (AFL) national draft is associated with individual game performance metrics. Physical/technical skill performance metrics were collated from all participants in the 2014 national under 18 (U18) championships (18 games) drafted into the AFL (n = 65; 17.8 ± 0.5 y); 232 observations. Players were subdivided into draft position (ranked 1–65) and then draft round (1–4). Here, earlier draft selection (i.e., closer to 1) reflects a more desirable player. Microtechnology and a commercial provider facilitated the quantification of individual game performance metrics (= 16). Linear mixed models were fitted to data, modelling the extent to which draft position was associated with these metrics. Draft position in the first/second round was negatively associated with “contested possessions” and “contested marks”, respectively. Physical performance metrics were positively associated with draft position in these rounds. Correlations weakened for the third/fourth rounds. Contested possessions/marks were associated with an earlier draft selection. Physical performance metrics were associated with a later draft selection. Recruiters change the type of U18 player they draft as the selection pool reduces. juniors with contested skill appear prioritised.  相似文献   
28.
29.
Abstract

Correspondence study represents the first and most persistent distance education format in American universities. Later called independent study, it enabled universities to disseminate instruction far beyond their campuses. Yet, national‐level leadership provided by the National University Continuing Education Association (NUEA) and its divisions has been relatively restrained. In contrast, leadership in the private correspondence school sector has been assertive, and sometimes even aggressive. The NUEA and its members shunned this approach, choosing instead to lead by persuasion and example. The NUEA developed standards of practice concerned primarily with replicating on‐campus teaching styles and values, rather than the promotion of distance education. With the abolition of its division structure, the NUEA's successor, the University Continuing Education Association (UCEA), has opted out of a leadership role in independent study. This paper concludes that the NUEA's initial attempt at leadership in distance education— while reasoned and principled—contained flaws that made failure inevitable.  相似文献   
30.
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