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   287篇
  免费   3篇
教育   172篇
科学研究   52篇
各国文化   9篇
体育   13篇
文化理论   5篇
信息传播   39篇
  2023年   2篇
  2022年   9篇
  2021年   10篇
  2020年   10篇
  2019年   13篇
  2018年   20篇
  2017年   16篇
  2016年   13篇
  2015年   9篇
  2014年   18篇
  2013年   49篇
  2012年   15篇
  2011年   23篇
  2010年   11篇
  2009年   11篇
  2008年   9篇
  2007年   5篇
  2006年   7篇
  2005年   6篇
  2004年   2篇
  2003年   2篇
  2002年   2篇
  2001年   1篇
  2000年   2篇
  1999年   1篇
  1997年   5篇
  1995年   1篇
  1992年   1篇
  1991年   1篇
  1989年   2篇
  1988年   2篇
  1983年   2篇
  1982年   1篇
  1981年   2篇
  1980年   3篇
  1979年   2篇
  1978年   1篇
  1975年   1篇
排序方式: 共有290条查询结果,搜索用时 15 毫秒
221.
This study examined the associations between pre-game wellness and changes in match running performance normalised to either (i) playing time, (ii) post-match RPE or (iii) both playing time and post-match RPE, over the course of a field hockey tournament. Twelve male hockey players were equipped with global positioning system (GPS) units while competing in an international tournament (six matches over 9 days). The following GPS-derived variables, total distance (TD), low-intensity activity (LIA; <15?km/h), high-intensity running (HIR; >15?km/h), high-intensity accelerations (HIACC; >2?m/s2) and decelerations (HIDEC; >?2?m/s2) were acquired and normalised to either (i) playing time, (ii) post-match RPE or (iii) both playing time and post-match RPE. Each morning, players completed ratings on a 0–10 scale for four variables: fatigue, muscle soreness, mood state and sleep quality, with cumulative scores determined as wellness. Associations between match performances and wellness were analysed using Pearson’s correlation coefficient. Combined time and RPE normalisation demonstrated the largest associations with Δwellness compared with time or RPE alone for most variables; TD (r?=??0.95; ?1.00 to ?0.82, p?=?.004), HIR (r?=??0.95; ?1.00 to ?0.83, p?=?.003), LIA (r?=??0.94; ?1.00 to ?0.81, p?=?.026), HIACC (r?=??0.87; ?1.00 to ?0.66, p?=?.004) and HIDEC (r?=??0.90; ?0.99 to ?0.74, p?=?.008). These findings support the use of wellness measures as a pre-match tool to assist with managing internal load over the course of a field hockey tournament.

Highlights

  • Fixtures during international field hockey tournaments are typically congested and impose high physiological demands on an athlete. To minimise decrements in running performance over the course of a tournament, measures to identify players who have sustained high internal loads are logically warranted.

  • The present study examined the association between changes in simple customised psychometric wellness measures, on changes in match running performance normalised to (i) playing time, (ii) post-match RPE and (iii) playing time and post-match RPE, over the course of a field hockey tournament.

  • Changes in match running performance were better associated to changes in wellness (r = ?0.87 to ?0.95), when running performances were normalised to both time and RPE compared with time or RPE alone.

  • The present findings support the use of wellness measures as a pre-match tool to assist with managing internal load over the course of a field hockey tournament. Improved associations between wellness scores and match running performances were evident, when running variables were normalised to both playing time and post-match RPE.

  相似文献   
222.
PurposeThis study aimed to assess the effectiveness and time course for improvements in explosive actions through resistance training (RT) vs. plyometric training (PT) in prepubertal soccer players.MethodsThirty-four male subjects were assigned to: a control group (n = 11); an RT group (5 regular soccer training sessions per week, n = 12); a PT group (3 soccer training sessions and 2 RT sessions per week, n = 11). The outcome measures included tests for the assessment of muscle strength (e.g., 1 repetition maximum half-squat test), jump ability (e.g., countermovement jump, squat jump, standing long jump, and multiple 5 bounds test), linear speed (e.g., 20 m sprint test), and change of direction (e.g., Illinois change of direction test).ResultsThe RTG showed an improvement in the half-squat (Δ = 13.2%; d = 1.3, p < 0.001) and countermovement jump (Δ = 9.4%; d = 2.4, p < 0.001) at Week 4, whereas improvements in the 20-m sprint (Δ = 4.2%; d = 1.1, p < 0.01); change of direction (CoD) (Δ = 3.8%; d = 2.1, p < 0.01); multiple 5 bounds (Δ = 5.1%; d = 1.5, p < 0.05); standing long jump (Δ = 7.2%; d = 1.2, p < 0.01); squat jump (Δ = 19.6%; d = 1.5, p < 0.01); were evident at Week 8. The PTG showed improvements in CoD (Δ = 2.1%; d = 1.3, p < 0.05); standing long jump (Δ = 9.3%; d = 1.1, p < 0.01); countermovement jump (Δ = 16.1%; d = 1.2, p < 0.01); and squat jump (Δ = 16.7%; d = 1.4, p < 0.01); at Week 8 whereas improvements in the 20-m sprint (Δ = 4.1%; d = 1.3, p < 0.01); and multiple 5 bounds (Δ = 7.4%; d = 2.4, p < 0.001); were evident only after Week. The RT and PT groups showed improvements in all sprint, CoD, and jump tests (p < 0.05) and in half-squat performance, for which improvement was only shown within the RTG (p < 0.001).ConclusionRT and PT conducted in combination with regular soccer training are safe and feasible interventions for prepubertal soccer players. In addition, these interventions were shown to be effective training tools to improve explosive actions with different time courses of improvements, which manifested earlier in the RTG than in the PTG. These outcomes may help coaches and fitness trainers set out clear and concise goals of training according to the specific time course of improvement difference between RT and PT on proxies of athletic performance of prepubertal soccer players.  相似文献   
223.
224.
ABSTRACT

The study purpose was to use Inertial Measurement Units (IMUs) to objectively assess children’s motor competence in seven movement skills. Fourteen children aged from seven to 12 years (M = 9.64) participated. Children were asked to perform up to 10 trials of each skill. Children performed the skills, which were captured by XSENS MVN Awinda wireless motion capture, and video. Skills were assessed from video as per the criteria from the Test of Gross Motor Development 3. Initially, 17 IMU sensors were used for signal processing, but this was restricted to four sensors (wrists and ankles) to be more feasible for field assessment. Results of the signal testing against its modelled “Good” signal, showed the skip was classified correctly each time, as was the sidestep. Accuracy % rates for each skill were: kick (95.2), catch (95.0), throw (80.5), jump (78.9), and hop (76.9). Using signal processing-based methods via four sensors was a reliable and feasible way to assess seven motor skills in children. This approach means monitoring and assessment of children’s skills can be objective, which will potentially reduce the time involved in motor skill assessment and analysis for research, clinical, sport and education purposes.  相似文献   
225.
226.
227.
228.

YouTube has become a global platform for learning and teaching. Its design as a social medium, its rapidly growing content and the obscurity of its search and recommendation system, however, frequently leave users with suboptimal results. Trying to give guidance, many professional websites started to publish ranked lists of educational channels. These lists, however, are highly non-conjoint and different in length, which challenges their general usefulness. This study first highlights some aspects and issues related to ranking YouTube’s educational channels by a qualitative and quantitative analysis of 193 lists collected from 101 websites. Then, an iterative multi-algorithm approach is proposed to derive aggregated ranked lists starting from these online lists for three categories: general education, science and history. The aggregated lists were then correlated with surface features of the channels including the channel’s lifetime and the total number of videos, views and subscribers. Also, an alternative rating-based ranking was established by analysing a total of 2900 videos from the different channels. The results show that the aggregated ranked list of science channels has strong correlation with surface channel features. In contrast, the aggregated ranks of history channels are more correlated with viewers’ positive ratings. The aggregated ranks of general education channels neither relate to channel features nor to viewers’ ratings. Based on these findings several remarks and recommendations for the generation, usage, and research on ranked lists and rank aggregation of YouTube’s educational channels are given.

  相似文献   
229.
Question-answering has become one of the most popular information retrieval applications. Despite that most question-answering systems try to improve the user experience and the technology used in finding relevant results, many difficulties are still faced because of the continuous increase in the amount of web content. Questions Classification (QC) plays an important role in question-answering systems, with one of the major tasks in the enhancement of the classification process being the identification of questions types. A broad range of QC approaches has been proposed with the aim of helping to find a solution for the classification problems; most of these are approaches based on bag-of-words or dictionaries. In this research, we present an analysis of the different type of questions based on their grammatical structure. We identify different patterns and use machine learning algorithms to classify them. A framework is proposed for question classification using a grammar-based approach (GQCC) which exploits the structure of the questions. Our findings indicate that using syntactic categories related to different domain-specific types of Common Nouns, Numeral Numbers and Proper Nouns enable the machine learning algorithms to better differentiate between different question types. The paper presents a wide range of experiments the results show that the GQCC using J48 classifier has outperformed other classification methods with 90.1% accuracy.  相似文献   
230.
The main objective of the current study is to examine the role of the statistical relation between BCL2 gene (Ala43Thr) single nucleotide polymorphism and growth hormone (GH1) levels in Egyptian HCV genotype-4 patients before and after treatment with pegylated interferon plus ribavirin. Eighty patients with HCV genotype-4 and 40 healthy volunteers as controls were enrolled in the prospective study. Gene polymorphism of BCL2 (Ala43Thr) using PCR-RFLP technique and GH1 concentrations using ELISA procedure were measured for all patients and controls. The present study resulted that Responder HCV genotype-4 Patients, with BCL2 43Ala genotype, have high significant increase in pre-treatment GH1 levels (>1 ng/ml); which represent normal levels, as compared to non-responders pre-treatment GH1 levels (<1 ng/ml); which represent low concentrations. We concluded that HCV genotype-4 patients who have normal GH1 concentrations and BCL-2 43Ala genotype can successfully achieve response to interferon based therapy.  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