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71.
The relationship between peak height velocity and physical performance in youth soccer players 总被引:1,自引:1,他引:0
Philippaerts RM Vaeyens R Janssens M Van Renterghem B Matthys D Craen R Bourgois J Vrijens J Beunen G Malina RM 《Journal of sports sciences》2006,24(3):221-230
Longitudinal changes in height, weight and physical performance were studied in 33 Flemish male youth soccer players from the Ghent Youth Soccer Project. The players' ages at the start of the study ranged from 10.4 to 13.7 years, with a mean age of 12.2 +/- 0.7 years. Longitudinal changes were studied over a 5 year period. Peak height velocity and peak weight velocity were determined using non-smoothed polynomials. The estimations of peak height velocity, peak weight velocity and age at peak height velocity were 9.7 +/- 1.5 cm x year-1, 8.4 +/- 3.0 kg x year-1 and 13.8 +/- 0.8 years, respectively. Peak weight velocity occurred, on average, at the same age as peak height velocity. Balance, speed of limb movement, trunk strength, upper-body muscular endurance, explosive strength, running speed and agility, cardiorespiratory endurance and anaerobic capacity showed peak development at peak height velocity. A plateau in the velocity curves was observed after peak height velocity for upper-body muscular endurance, explosive strength and running speed. Flexibility exhibited peak development during the tear after peak height velocity. Trainers and coaches should be aware of the individual characteristics of the adolescent growth spurt and the training load should also be individualized at this time. 相似文献
72.
Based on ideas from subjective uncertainty reduction theory, we examined the extent to which individuals hold similar sport team preferences to their family and friends. We also assessed the extent to which perceived sport importance and personal need for structure are influential in the development of team identification. Australian high school students aged 15.5+/-1.0 years (mean+/-s) completed questionnaires containing the Personal Need for Structure Scale, the Relational-Interdependent Self-Construal scale, a Team Identification Scale, and items assessing perceptions of sport importance and team preferences. As expected, correlations indicated that preferences for sport teams were significantly related to the preferences of family and friends. Separate analyses of variance confirmed the remaining hypotheses. More specifically, individuals who perceived that sport was important identified with the team more than individuals who perceived sport to be less important. Also, individuals high in personal need for structure scored higher in cognitive/affective team identification than those low in this need. Individuals with differing needs for structure did not differ in their scores on other dimensions of team identification. The results support the notion that cognitive/emotional attachments to sport teams are influenced by perceptions of the importance of sport and by needs for subjective structure. It is possible that other psychological motives, such as the desire for self-esteem, facilitate the development of evaluative dimensions of team identification. 相似文献
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74.
Myers ND Wolfe EW Maier KS Feltz DL Reckase MD 《Research quarterly for exercise and sport》2006,77(4):451-463
This study extended validity evidence for multidimensional measures of coaching competency derived from the Coaching Competency Scale (CCS; Myers, Feltz, Maier, Wolfe, & Reckase, 2006) by examining use of the original rating scale structure and testing how measures related to satisfaction with the head coach within teams and between teams. Motivation, game strategy, technique, and character building comprised the dimensions of coaching competency. Data were collected from athletes (N = 585) nested within intercollegiate men's (g = 8) and women's (g = 13) soccer and women's ice hockey (g = 11) teams (G = 32). Validity concerns were observed for the original rating scale structure and the predicted positive relationship between motivation competency and satisfaction with the coach between teams. Validity evidence was offered for a condensed post hoc rating scale and the predicted relationship between motivation competency and satisfaction with the coach within teams. 相似文献
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77.
A bond graph model is derived for the geometric constraints of a three-axis flight table. Gimbal dynamics are easily added even in asymmetrical and unbalanced cases. A method is introduced to make the local dependent inertias computable. The bond graph compares favourably to the Lagrangian approach as to modelling effort and accessibility of intermediate variables as well as having computational advantages. 相似文献
78.
The chief purpose of this study was to identify characteristics that distinguish approach as an attachment behavior from approach serving other behavioral systems. Locomotor approaches of 16 male and 10 female white middle-class infants to an attachment figure (the mother) and to a nonattachment figure (the visitor-observer) were examined under naturalistic conditions at home. Observations were made during 4-hour home visits at 3-week intervals; those from 26 to 54 weeks were used. When approach was examined in a free-choice situation and without regard to behavioral context, infants approached the mother proportionally (though slightly) more often than the visitor (p less than .05). In 2 behavioral contexts, however, spontaneous infant approaches were sharply differential to the mother; approaches accompanied by crying and approaches terminating in a pickup appeal were directed almost exclusively to the mother (p less than .0001 for both). Touching upon completion of the approach was not differential, except in the context of a pickup appeal. Object-oriented approaches were more often directed to the visitor than to the mother (p less than .002) and may be either exploratory or affiliative. It is suggested that neither approach nor touching can be assumed to serve the attachment system without consideration of context- both environmental and behavioral. 相似文献
79.
48 healthy neonates born to multiparae were randomly assigned to view a moving stimulus either in the horizontal or the upright position, with or without added vestibular stimulation and with or without pacifier sucking. The infant was shown a moving black line inside a strictly controlled visual environment provided by an apparatus which permitted horizontal and upright positioning and displacement of the infant. Visual tracking was recorded by a concealed TV camera positioned at a constant distance and angle from the infants' eyes in both positions. Quality of tracking during each of 4 trials was scored on a 7-point scale. Results indicate that vestibularproprioceptive stimulation provided to the infant either horizontally or semivertically significantly enhanced his visual tracking, whereas the upright position did not. Pacifier sucking also improved his performace. 相似文献
80.