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排序方式: 共有802条查询结果,搜索用时 765 毫秒
111.
The aim of this study was to quantify movements of Super 12 rugby players in competition because information on elite rugby players' movements is unavailable. Players were categorized into forwards [front (n = 16) and back row (n = 15)] and backs [inside (n = 9) and outside backs (n = 7)] and their movements analysed by video-based time motion analysis. Movements were classified as rest (standing, walking and jogging) and work (striding, sprinting, static exertion, jumping, lifting or tackling). The total time, number and duration of individual activities were assessed, with differences between groups evaluated using independent sample t-tests (unequal variances), while differences between halves were assessed with paired sample t-tests. Forwards had 7:47?min:s (95% confidence limits: 6:39 to 8:55?min:s, P<0.01) more time in static exertion than backs, but backs spent 0:52 (0:34 to 1:09, P = 0.01) min:s more time sprinting than forwards, and had a 0.7 (0.3 to 1.2, P = 0.01) s longer duration of each sprint. Forwards spent 7:31 (5:55 to 9:08) min:s more time in work activities (P = 0.01) and had 2.1 (1.3 to 2.8) s longer work durations (P<0.01) than backs. The results indicate frequent short duration (<4?s) work efforts followed by moderate duration (<20?s) rest for forwards, and extended (>100?s) rest duration for backs. High-intensity efforts involved static exertion for forwards (mean?±?standard deviation frequency = 80?±?17) and sprinting for backs (27?±?9). In conclusion, after nearly a decade since becoming professional, elite rugby union is still characterized by highly intense, intermittent movement patterns and marked differences in the competition demands of forwards and backs. 相似文献
112.
Fredric L. Goss William G. Herbert Thomas B. Kelso 《Research quarterly for exercise and sport》2013,84(3):292-294
Abstract Little research has investigated the observational learning process from a developmental perspective. The purpose of this study was to extend previous research by considering two factors: performance versus learning and sequencing versus form scores. Children 'N = 60) comprising two age groups (5-0 to 6-11 and 8-0 to 9-11 years) were randomly assigned to verbal rehearsal only, model only, or model plus verbal rehearsal conditions. The task was a 6 part motor skill sequence in which proper sequencing and quality of form were assessed. A 2 × 3 × 4 (age group by model type by trial blocks) repeated measures MANOVA revealed a significant three-way interaction. Older children performed equally well under any of the model type conditions during both performance and learning. For younger children, a model plus rehearsal was superior to rehearsal only on sequence and form at performance and learning and superior to model only on sequence scores during the first two performance trial blocks. Model only and model plus rehearsal conditions were equally effective on form scores. These results suggest that age differences exist in the modeling of motor skills under conditions varying in model type, sequence and form scores, and performance and learning phases. 相似文献
113.
John C.K. Wang Martin Hagger Woon Chia Liu 《Research quarterly for exercise and sport》2013,84(2):313-325
We examined the validity of the factor structure and invariance of the Perceived Locus of Causality (PLOC) scale instrument scores across two nations endorsing collectivist (Singapore) and individualist (Great Britain) cultural values. Results indicated that confirmatory factor analytic models of the PLOC exhibited adequate ft according to multiple criteria within each sample and across samples. There was invariance in the item-intercepts across the two cultures. In addition, the simplex-like pattern of relations among the PLOC constructs was confirmed within cultures and in invariance analyses. Finally, latent factor means analysis revealed that the British participants tended to rate less self-determined forms of motivation lower than and more self-determined forms of motivation higher than the Singaporean participants. 相似文献
114.
Nicholas D. Myers Ahnalee M. Brincks Mark R. Beauchamp 《Measurement in physical education and exercise science》2013,17(4):275-294
The primary purpose of this tutorial is to succinctly review some options for, and consequences of, centering Level 1 predictors in commonly applied cross-sectional two-level models. It is geared toward both practitioners and researchers. A general understanding of multilevel modeling is necessary prior to understanding the subtleties of centering decisions. A review of some high-quality journals within the broad discipline of exercise science provides evidence that multilevel modeling is used relatively infrequently in this field. Therefore, a secondary purpose is to introduce Measurement in Physical Education and Exercise Science readers to some core facets of multilevel modeling within the framework of this tutorial. A relevant dataset is used to demonstrate potential consequences of different centering decisions within a multilevel model. Depending on the model and the data, different centering decisions can exert non-trivial influence on the meaning of some model parameters, results from fitting the model, and subsequent conclusions. 相似文献
115.
116.
倪树范 《绵阳师范学院学报》2003,22(2):50-51,96
噪声是一个随机信号,其电压波形是没有规律的非正弦波。由于无法描述噪声电压的时间波形。从测量的角度看,对噪声电压的测量一般用有效值电压表直接进行。本文根据噪声可以用统计学的方法描述其特性,噪声电压的分布规律符合正态分布的特点,由噪声的概率密度函数和平均值电压表定度的关系给出了一种运用实验室常见的平均值电压表测量放大器噪声电压的方法及其测量中的注意事项与测量步骤。 相似文献
117.
118.
A statistical approach to evaluate the subjective perception of the annoyance caused by the vehicle noise was presented in this paper. After recording the noises of Sanfeng, Huali and Xiali at speeds of 30, 40, 50, 60, 70 and 80 km/h respectively, the annoyance of the vehicle noises was evaluated in the testing room using paired comparison method, and the sound quality metrics and subjective annoyance were then distilled. Loudness, sharpness, roughness, periodicity and impulsiveness were selected for each of the vehicle noises. By correlation analysis method, it can be found that loudness has a higher correlation (0.91) with annoyance than other parameters. Meanwhile, sharpness, periodicity, roughness and impulsiveness have correlation with subjective perception with correlation coefficients being 0.84,-0.82, 0.62 and 0.87, respectively. The result of multiple regression analysis shows that calculated annoyance obtained by the regression equation can explain the perceptual annoyance and the regressed evaluation model is feasible to evaluate the sound quality of vehicle. 相似文献
119.
加权循环不等式与其对偶不等式及其应用 总被引:1,自引:0,他引:1
文开庭 《贵州教育学院学报》2005,16(2):4-6
利用Cauchy不等式和幂平均不等式,研究了循环不等式的校正加权推广及其对偶推广,给出了推广结果的应用。 相似文献
120.
高小序 《鞍山师范学院学报》2007,9(5):14-17
《中庸》倍受古人推崇,其思想精华仍被世人运用,其精髓在于三“高“:高尚道德是其立世之本;高度自律是其存世之魂;高雅风度是其行事之道. 相似文献