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81.
Thigh muscle volume is a useful determinant of functional fitness. However, anthropometric prediction of muscle content is influenced by the variability of adipose tissue accumulation. The aims of this study were to predict thigh muscle and adipose tissue volumes from anthropometry and to assess the validity of the method by examining the various components of the measurements and the assumptions involved. The 19 participants (9 men, 10 women; age 23-49 years) varied in adiposity. They all underwent magnetic resonance imaging (MRI) of the upper leg and the eight men and two women with the lowest adiposity underwent detailed anthropometry involving girths and skinfolds. Using MRI as the reference method, muscle volume was predicted from anthropometry using a circular concentric model, and the assumptions inherent in the method were tested further using the MRI data alone. Muscle volume was best predicted by anthropometry in the 10 leanest participants using a five-slice truncated cone model that overestimated the mean MRI value by 30% ( R 2 = 0.95; standard error of estimate = 288 cm 3 ; P ? 0.001). A single skinfold plus girth measurement at the mid-thigh almost matched its predictive ability, but with an increased bias. Measurements of leg circumference by means of the two techniques agreed well. The assumption of a circular cross-section was valid. In contrast, the agreement between skinfold thickness measured by caliper and superficial adipose tissue thickness by MRI was poor, contributing to the scatter of fat and lean area comparisons. An anterior skinfold thickness measurement underestimated the area of superficial adipose tissue at that level, particularly at the most proximal and distal sites. Although these limitations increase the uncertainties of muscle volume determination by anthropometry, they do not prevent its valid prediction in leaner individuals. The prediction of superficial adipose tissue was poorer. 相似文献
82.
It is well known that sport and exercise play an important role in stimulating site-specific bone mineral density (BMD). However, what is less well understood is how these benefits dissipate throughout the body. Hence, the aim of the present study was to compare the BMD (recorded at nine sites throughout the skeleton) of 106 male athletes (from nine sports) with that of 15 male non-exercising age-matched controls. Given that BMD is known to increase with body mass and peak with age, multivariate and univariate analyses of covariance were performed to compare the BMD of the nine sports groups with controls (at all sites) using body mass and age as covariates. Our results confirmed a greater adjusted BMD in the arms of the upper-body athletes, the right arm of racket players and the legs of runners (compared with controls), supporting the site-specific nature (i.e. specific to the externally loaded site) of the bone remodelling response (all P?<0.01). However, evidence that bone mass acquisition is not just site-specific comes from the results of the rugby players, strength athletes, triathletes and racket players. The rugby players' adjusted BMD was the greatest of all sports groups and greater than controls at all nine sites (all P?<0.01), with differences ranging from 8% greater in the left arm to 21% in the lumbar spine. Similarly, the strength athletes' adjusted BMD was superior to that of controls at all sites (P?<0.05) except the legs. The adjusted BMD of the triathletes was significantly greater than that of the controls in both the arms and the legs as well as the thoracic and lumbar spine. The racket players not only had significantly greater right arm BMD compared with the controls but also a greater BMD of the lumbar spine, the pelvis and legs. In contrast, the low-strain, low-impact activities of keep-fit, cycling and rowing failed to benefit BMD compared with the age-matched controls. These results suggest that sporting activities involving high impact, physical contact and/or rotational forces or strains are likely to convey significant benefits not only to the loaded sites, but also to other unloaded peripheral and axial sites throughout the skeleton. 相似文献
83.
Alan M. Nevill Edward M. Winter Steve Ingham Adam Watts Georgios S. Metsios Arthur D. Stewart 《Journal of sports sciences》2013,31(9):1009-1016
Abstract The aim of the present study was to identify when body mass index (BMI) is unlikely to be a valid measure of adiposity in athletic populations and to propose a simple adjustment that will allow the BMI of athletes to reflect the adiposity normally associated with non-athletic populations. Using data from three previously published studies containing 236 athletes from seven sports and 293 age-matched controls, the association between adiposity (sum of 4 skinfold thicknesses, in millimetres) and BMI was explored using correlation, linear regression, and analysis of covariance (ANCOVA). As anticipated, there were strong positive correlations (r = 0.83 for both men and women) and slope parameters between adiposity and BMI in age-matched controls from Study 1 (all P < 0.001). The standard of sport participation reduced these associations. Of the correlations and linear-regression slope parameters between adiposity and BMI in the sports from Studies 2 and 3, although still positive in most groups, less than half of the correlations and slope parameters were statistically significant. When data from the three studies were combined, the ANCOVA identified that the BMI slope parameter of controls (5.81 mm · (kg · m?2)?1) was greater than the BMI slope parameter for sports (2.62 mm · (kg · m?2)?1) and middle-distance runners (0.94 mm · (kg · m?2)?1) (P < 0.001). Based on these contrasting associations, we calculated how the BMI of athletes can be adjusted to reflect the same adiposity associated with age-matched controls. This simple adjustment allows the BMI of athletes and non-athletes to be used with greater confidence when investigating the effect of BMI as a risk factor in epidemiological research. 相似文献
84.
Russell R. Pate Stewart G. Trost Gwen M. Felton Dianne S. Ward Marsha Dowda Ruth Saunders 《Research quarterly for exercise and sport》2013,84(3):241-248
Abstract The purpose of this study was to identify correlates of physical activity behavior in a sample of rural, predominantly African American youth. Three hundred sixty-one fifth-grade students from two rural counties in South Carolina (69% African American, median age = 11 years) completed a questionnaire designed to measure beliefs and social influences regarding physical activity, physical activity self-efficacy, perceived physical activity habits of family members and friends, and access to exercise and fitness equipment at home. After school physical activity and television watching were assessed using the Previous Day Physical Activity Recall (PDPAR). Students were classified as physically active according to a moderate physical activity standard: two or more 30-min blocks at an intensity of 3 METs (metabolic equivalents) or greater, and a vigorous physical activity standard: one or more 30-min blocks at an intensity of 6 METs or greater. According to the moderate physical activity standard, 34.9% of students were classified as low-active. Multivariate analysis revealed age, gender, television watching, and exercise equipment at home to be significant correlates of low activity status. According to the vigorous physical activity standard, 32.1% of the students were classified as low-active. Multivariate analysis revealed age, gender, television watching, and self-efficacy with respect to seeking support for physical activity to be significant correlates of low activity status. In summary, gender and the amount of television watching were found to be the most important correlates of physical activity in rural, predominantly African American youth. 相似文献
85.
Renata Phelps Stewart Hase Allan Ellis 《British journal of educational technology : journal of the Council for Educational Technology》2005,36(1):67-84
Notions of competency have dominated the computer education literature, and have underpinned Competency‐Based Training (CBT) in information technology at all levels of education and training. The emergence of counter‐narratives underpinned by the capability movement, have as yet had minimal impact on practice in computer education. New discourses in educational theory and practice which are founded on non‐linear approaches to learning and teaching provide added impetus to engage in the competency/capability debate, and re‐examine our approaches to computer education. This paper explores complexity theories and demonstrates how complexity's pedagogical implications can lead to new models for understanding computer learning and teaching. A new model for conceptualising end‐user computer education is presented that was derived from a three‐year action research initiative with pre‐service teachers. 相似文献
86.
41 middle-class families were interviewed at 1 month prepartum and 1, 4, 8, and 12 months after the birth of a second child to assess the reaction and adjustment of firstborn children to this event. Family members were also observed in a semistructured play session in order to obtain information concerning changes in familial interaction patterns. A log linear analysis was conducted to fit a hierarchical model to a 2 (child gender) X 2 (infant gender) X 4 (time of measurement relative to birth of infant) X 2 (presence or absence of problematic regressive behavior) X 14 (type of problematic behavior reported) matrix. A model with 2 statistically significant effects was found to fit the observed frequency matrix quite well, goodness-of-fit (GF) chi 2(312, N = 2,296) = 97.47, p less than .99. This model suggests (1) that the type of response displayed by the firstborns varied as a function of time since the birth; that their initial responses were either imitations of the infant or confrontations with the mother or infant, whereas responses at 4 months postpartum were characterized by numerous anxiety behaviors but fewer imitations or confrontations, and later responses were primarily confrontations with the increasingly intrusive and independent infant; and (2) that a greater frequency of problematic behavior was reported by the mothers of same-sex sibling dyads, especially at the 1- and 8-month postpartum assessments. Observational data indicated that mothers dramatically decreased their interactions with the firstborn children over time but that fathers tended to remain relatively stable in their frequencies of interaction. 相似文献
87.
E. Mark Mahone Teresa L. Miller Christine W. Koth Stewart H. Mostofsky Melissa C. Goldberg Martha B. Denckla 《Psychology in the schools》2003,40(4):331-340
Reviews involving the Wechsler Scales for children suggest that Full Scale IQ scores on the Wechsler Intelligence Scale for Children, Third Edition, average 5 to 6 points lower than scores on the second edition of the scale [WISC‐R, Wechsler, D. (1974). Zimmerman & Woo‐Sam, 1997], with the differences distributed disproportionately over subtests, i.e., with larger discrepancies found within the Performance Scale (Wechsler, 1991). Changes on the revised subtests of the WISC‐III Performance Scale may place children with ADHD at a disadvantage compared to their performance on analogous WISC‐R subtests. We examined IQ test performance in 122 unmedicated children with ADHD (61 given the WISC‐R, 61 given the WISC‐III), and 46 children from a healthy, comparison group (23 given the WISC‐R, 23 given the WISC‐III). The ADHD and comparison group samples were matched for sex and for Verbal IQ between WISC‐R and WISC‐III. Children with ADHD had significantly lower Performance IQ on WISC‐III compared to the WISC‐R, with the Picture Arrangement subtest showing the most significant difference. In contrast, there were no significant differences between the WISC‐R and WISC‐III cohorts on Performance IQ or any Performance subtests among the comparison group. These findings highlight the importance of examining the comparability of ability test revisions among clinical and non‐clinical populations, and will be especially salient when the WISC‐III is revised. © 2003 Wiley Periodicals, Inc. Psychol Schs 40: 331–340, 2003. 相似文献
88.
Gay B. Stewart 《Journal of Science Education and Technology》1997,6(3):173-191
In this paper, we present a system for formally characterizing elements of an introductory science class, measuring the performance of a class based on this characterization, and modeling the value of the class based on the measurements. This system allows the iterative improvement of any educational presentation through a model, test, iterate cycle. We propose formal practices involved in iteratively improving an educational experience be called educational engineering. 相似文献
89.
Jacqueline A. Brown Shane R. Jimerson Erin Dowdy Victoria Gonzalez Kaitlyn Stewart 《Psychology in the schools》2012,49(9):864-875
Because school violence is widespread, social and emotional competence must be targeted. Second Step is a social and emotional violence‐prevention curriculum that teaches prosocial skills and reduces aggressive behavior. The purpose of this study was to examine the effects of Second Step implementation on students (N = 403) in preschool through fourth grade who were predominately Latino, English language learners, and from families with low socioeconomic status. The data of 165 out of the 403 students were included in the present study. Analyses consisted of paired‐samples t‐tests to identify changes in social and emotional knowledge and behavioral and emotional risk. Results showed that there was a significant increase in both social and emotional knowledge and behavioral and emotional risk following the implementation of Second Step. These results are discussed with regard to previous and future research, limitations, and implications for school practice. 相似文献
90.
Georgina Stewart 《Educational Philosophy and Theory》2014,46(11):1270-1275
AbstractGoals for adding philosophy to the school curriculum centre on the perceived need to improve the general quality of critical thinking found in society. School philosophy also provides a means for asking questions of value and purpose about curriculum content across and between subjects, and, furthermore, it affirms the capability of children to think philosophically. Two main routes suggested are the introduction of philosophy as a subject, and processes of facilitating philosophical discussions as a way of establishing classroom ‘communities of inquiry’. This article analyses the place of philosophy in the school curriculum, drawing on three relevant examples of school curriculum reform: social studies, philosophy of science and Kura Kaupapa Māori. 相似文献