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851.
This study was designed to examine whether participants who could control the schedule of performance feedback (KP) would learn differentially from those who received a rigid feedback schedule while learning a complex task. Participants (N = 48) were randomly assigned to self-controlled KP (SELF), summary KP (SUMMARY), yoked control (YOKE), or knowledge of results only (KR) conditions. Data collection consisted of an acquisition phase and a 4-day retention phase during which right-handed participants performed a left-handed ball throw. Overall, throwing form improved across trial blocks during acquisition, with the SUMMARY, SELF, and YOKE groups showing more improvement than the KR group. During retention, the SELF group retained a higher level of throwing form and accuracy in comparison to the other groups. Results suggest that when given the opportunity to control the feedback environment, learners require relatively less feedback to acquire skills and retain those skills at a level equivalent to or surpassing those who are given more feedback but receive it passively.  相似文献   
852.
Abstract

The present study aimed to establish whether 2 weeks of high-intensity interval training would have a beneficial effect on aerobic fitness, fat oxidation, blood pressure and body mass index (BMI) in healthy adolescent boys. Ten adolescent boys (15.1 ± 0.3 years, 1.3 ± 0.2 years post-estimated peak height velocity) completed six sessions of Wingate-style high-intensity interval training over a 2-week period. The first session consisted of four sprints with training progressed to seven sprints in the final session. High-intensity interval training had a beneficial effect on maximal O2 uptake (mean change, ±90% confidence intervals: 0.19 L · min?1, ±0.19, respectively), on the O2 uptake at the gas exchange threshold (0.09 L · min?1, ±0.13) and on the O2 cost of sub-maximal exercise (–0.04 L · min?1, ±0.04). A beneficial effect on the contribution of lipid (0.06 g · min?1, ±0.06) and carbohydrate (–0.23 g · min?1, ±0.14) oxidation was observed during sub-maximal exercise, but not for the maximal rate of fat oxidation (0.04 g · min?1, ±0.08). Systolic blood pressure (1 mmHg, ±4) and BMI (0.1 kg · m2, ±0.1) were not altered following training. These data demonstrate that meaningful changes in health outcomes are possible in healthy adolescent boys after just six sessions of high-intensity interval training over a 2-week period.  相似文献   
853.
Abstract

The present study tested whether there were significant sport competition anxiety differences among sex-typed, androgynous, and cross sex-typed subjects and whether these differences were consistent with gender schema theory (Bem, 1981b).

Approximately 700 subjects were administered the Bem Sex-Role Inventory (BSRI) and, using two methods of scoring, 216 subjects were selected because of being either sex-typed (masculine males, feminine females), cross sex-typed (masculine females, feminine males) or androgynous (males and females who have strong masculine and feminine dimensions). Each subject was tested for competition anxiety using the Sport Competition Anxiety Test (SCAT). A one-way ANOVA of SCAT scores by group was significant, F(5,210) = 6.52, p < .001. Post-hoc analysis revealed that feminine females had significantly more competitive trait anxiety than all other groups and androgynous females were more anxious than masculine males (p < .05). The results are discussed in terms of gender schema theory.  相似文献   
854.
Abstract

This study investigated the hypothesis that systematic changes in efficiency (speed) of saccadic eye movement speed (SEMS) are accompanied by parallel improvements in associated motor responses or vice versa. Seventy-two individuals were classified according to SEMS and randomly assigned to batting practice, SEMS training, or control groups. Each of the two experimental groups practiced a total of ten hours under their respective training conditions. All individuals were pre- and posttested on batting performance. Results indicated that prior to training, individuals with faster SEMS were significantly better batters than those with slower SEMS. Training through actual batting produced significant increases in both SEMS and batting performance. Training through a SEMS program resulted primarily in significant improvements in SEMS. However, some evidence was found to indicate that observable (although less dramatic) changes also occurred in batting performance for this group.  相似文献   
855.
Eighteen volunteer female subjects received preliminary instruction in a simple gymnastics bench sequence. They were then given a pre‐intervention test on a bench at ground level. Self‐reported distress, an independent observer's ratings of distress and heart rates were monitored immediately prior to performance of the sequence. Performances were also videotaped and formally scored by a qualified gymnastics judge. Subjects were then randomly assigned to a stress inoculation training group or a ‘no stress management’ training control group. Stress inoculation group subjects then received seven sessions of training in relaxation, imagery and making self‐statements in order to develop a set of coping skills. Control group subjects also received seven training sessions during which they practised a series of coordination exercises, but no psychological stress management training was given to this group.

All subjects were then re‐tested on the bench sequence but this time at a height of 1.52 m. Self‐reported stress, observer's ratings of distress and heart rate were recorded as before. Performance was again videotaped for scoring. The stress inoculation group reported significantly less stress prior to the test on the elevated beam than the control group. However, the groups did not differ in terms of heart rate. Further, the stress inoculation group performed reliably better than the control group on the elevated bench.  相似文献   
856.
We have previously shown that single‐leg training results in improved endurance for exercise with the untrained leg (UTL) as well as for exercise with the trained leg (TL). The purpose of this study was to see whether the improved endurance of the untrained leg could be explained on the basis of changes in muscle metabolism. Exercise time to exhaustion at 80% of maximum oxygen uptake (VO2 max) was determined for each leg separately, pre‐ and post‐training. Muscle metabolite concentrations were measured pre‐ and post‐training in biopsy samples obtained immediately before this endurance test and at the pre‐training point of exhaustion (END1). After six weeks of single‐leg training endurance time was increased for both the UTL and the TL (UTL 34.0+16.4 min vs 97.9±26.3 min, P<0.01; TL 28.3 + 10.1 min vs 169.0 + 32.6 min, P < 0.01). No changes in muscle metabolite concentrations were found in resting muscle. Training increased muscle ATP (P <0.05) and glycogen (P <0.01) concentrations and decreased muscle lactate concentration (P<0.05) in the TL at END1. No significant changes in muscle metabolite concentrations were found for the UTL. The improved endurance of the contralateral limb after single‐leg training could not be explained on the basis of changes in muscle metabolism.  相似文献   
857.
In this study, we examined the visual search strategies used during observation of video and point-light display models. We also assessed the relative effectiveness of video and point-light models in facilitating the learning of task outcomes and movement patterns. Twenty-one female novice soccer players were divided equally into video, point-light display and no-model (control) groups. Participants chipped a soccer ball onto a target area from which radial and variable error scores were taken. Kinematic data were also recorded using an opto-electrical system. Both a pre- and post-test were performed, interspersed with three periods of acquisition and observation of the model. A retention test was completed 2 days after the post-test. There was a significant main effect for test period for outcome accuracy and variability, but observation of a model did not facilitate outcome-based learning. Participants observing the models acquired a global movement pattern that was closer to that of the model than the controls, although they did not acquire the local relations in the movement pattern, evidenced by joint range of motion and angle-angle plots. There were no significant differences in learning between the pointlight display and video groups. The point-light display model group used a more selective visual search pattern than the video model group, while both groups became more selective with successive trials and observation periods. The results are discussed in the context of Newell's hierarchy of coordination and control and Scully and Newell's visual perception perspective.  相似文献   
858.
The aim of this study was to determine the influence of breathing frequency and tidal volume on resting heart rate variability in children aged 9 years ( n = 29) and 16 years ( n = 19). Heart rate variability was measured in four conditions: (1) without the control of ventilation followed at random by (2) a fixed breathing frequency of 12 breaths· min -1 , (3) a breathing frequency of 12 breaths· min -1 but with a fixed tidal volume of 30% vital capacity and (4) a fixed breathing frequency of 6 breaths·min -1 and a tidal volume of 30% vital capacity. A total of 128 RR intervals (the time between two spikes in the heart rate) were detected and absolute high- and low-frequency spectral components were calculated using autoregressive modelling. The younger children were unable to control ventilation to achieve conditions 3 and 4; therefore, a 2 2 2 (group 2 condition) analysis of variance was used to analyse conditions 1 and 2. There were significant interactions between group and heart rate variability conditions for the low-frequency component and the ratio of low to high frequencies ( P ? 0.001). The main effect for condition showed that at 12 breaths· min -1 with no fixed tidal volume there was a significantly higher standard deviation of the RR interval, total power and high-frequency ( P ? 0.01) and lowfrequency spectral components ( P ? 0.05) than in the condition with no ventilatory control. Across the four breathing conditions for the older participants, the high-frequency spectral component was significantly higher in the condition at 6 breaths· min -1 with a fixed tidal volume than in that with no ventilatory control ( P ? 0.005); the ratio of high to low frequencies was significantly lower for the spontaneous condition than those performed at 12 breaths· min -1 ( P ? 0.001). The results provide evidence of the need for ventilatory control when assessing short-term resting heart rate variability in children.  相似文献   
859.
The hypothesis that endurance training impairs sprinting ability was examined. Eight male subjects undertook a 30‐s sprint test on a cycle ergometer before and after 6 weeks of cycling training for endurance. Maximum oxygen uptake (VO2 max) and submaximum endurance were determined to evaluate the influence of the training regimen on endurance performance. Endurance was defined as the time to exhaustion at a relative exercise intensity of 85% VO2 max. Maximum oxygen uptake was increased by 18% post‐training (3.29 ± 0.291 min–1 versus 3.89±0.491 min–1; P <0.01), but endurance at the same absolute work rate as pre‐training was increased by more than 200% (32.2 ±11.4 min versus 97.8 + 27.3 min; P <0.01). These improvements were accompanied by changes in the cardiovascular and metabolic responses to standard, submaximum exercise. Despite the improvements in endurance, neither performance during the cycle sprint test nor the increase in blood lactate concentration during the sprint was influenced by endurance training. For short‐term cycling training, these findings reinforce the concept of training specificity whilst demonstrating that decrements in sprint performance are not a necessary consequence of improved endurance.  相似文献   
860.
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