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181.
It is currently unclear how football participation affects knee-joint muscle balance, which is widely considered a risk factor for hamstrings injury. This study compared the angle-specific functional hamstring-to-quadriceps (H:Q) ratio (hamstrings eccentric torque as a ratio of quadriceps concentric torque at the same knee-joint angle) of football players with recreationally active controls. Ten male footballers and 14 controls performed maximal voluntary isometric and isovelocity concentric and eccentric contractions (60, 240 and 400° s?1) of the knee extensors and flexors. Gaussian fitting to the raw torque values was used to interpolate torque values for knee-joint angles of 100–160° (60° s?1), 105–160° (240° s?1) and 115–145° (400° s?1). The angle-specific functional H:Q ratio was calculated from the knee flexors eccentric and knee extensors concentric torque at the same velocity and angle. No differences were found for the angle-specific functional H:Q ratio between groups, at any velocity. Quadriceps and hamstrings strength relative to body mass of footballers and controls was similar for all velocities, except concentric knee flexor strength at 400° s?1 (footballers +40%; P < 0.01). In previously uninjured football players, there was no intrinsic muscle imbalance and therefore the high rate of hamstring injuries seen in this sport may be due to other risk factors and/or simply regular exposure to a high-risk activity.  相似文献   
182.
Sports science research is traditionally monodisciplinary despite calls for an interdisciplinary focus. The primary purpose of this systematic review was to identify studies on talent identification, talent selection and competition performance to determine whether interdisciplinary research is being conducted. Thirty-six studies met the selection criteria. These studies were critiqued relative to sport, skill level, sport science sub-disciplines included, and whether the research was multidisciplinary or interdisciplinary. The secondary purpose of the review was to critique the level of analysis and level of representative task design in performance tests used in the studies. Twenty-five studies were categorised as interdisciplinary, with 11 categorised as multidisciplinary. Thirteen sports were represented with soccer the most frequent followed by field hockey, Australian Rules football, handball and rugby league. Thirty-two studies completed their analysis at a group level and four at an individual level. A total of 337 performance tests were rated for representative task design with 64 categorised as low, 123 as medium and 150 as high. The results pertaining to interdisciplinary studies and individual analyses are discussed in relation to constraints theory, which predicts that interacting variables can explain sport performance. Sports science research is beginning to fulfil the call for interdisciplinary research. Future research, however, needs to consider individual analyses and representative task design of tests to progress sports science knowledge.  相似文献   
183.
The dielectrophoretic behavior of active, dead, and dormant Mycobacterium smegmatis bacterial cells was studied. It was found that the 72-h-old dormant cells had a much higher effective particle conductivity (812±10 μS cm−1), almost double that of active cells (560±20 μS cm−1), while that of dead (autoclaved) M. smegmatis cells was the highest (950±15 μS cm−1) overall. It was also found that at 80 kHz, 900 μS cm−1 dead cells were attracted at the edges of interdigitated castellated electrodes by positive dielectrophoresis, but dormant cells were not. Similarly, at 120 kHz, 2 μS cm−1 active cells were attracted and dormant cells were not. Using these findings a dielectrophoresis-based microfluidic separation system was developed in which dead and active cells were collected from a given cell suspension, while dormant cells were eluted.  相似文献   
184.
185.
Little empirical research has compared the manufacturing strategies of corporate and independent new ventures. This study explores these differences with data from the young, science-based biotechnology industry, and examines the performance effects of manufacturing strategy variables including scope, competitive thrust, and capabilities. The results show that the corporate and independent biotechnology new ventures pursue significantly different manufacturing strategies, and that different dimensions of manufacturing strategies affect the performance of corporate vs. independent ventures quite differently.  相似文献   
186.
187.
Four experiments investigated the stimulus properties of female mice that influence ultrasound production by adult males. Female urine alone was less effective in evoking ultrasounds than was the female in male-female pairs. Visual cues were not necessary, since there was no difference in the incidence or latency of ultrasounds from male-female pairs when tested in light and dark conditions. A presently unspecified chemical cue produced by females, whose effectiveness is mediated by olfaction, was sufficient to evoke ultrasounds from male mice. The role of this chemical cue in a multimodal sequential communicative chain is discussed.  相似文献   
188.
Secondary education in Swaziland has rapidly expanded in the decade or so since independence. Alongside this achievement has been a growing apprehension that the modern sector's capacity to generate employment is not commensurate with the rising number of educated young people leaving secondary school. The emergence of a ‘school leaver problem’ as disenchanted educated youngsters remained unemployed was therefore seen as a real possibility towards the end of the 1970s. Such considerations formed the backcloth to tracer surveys conducted in 1979 which investigated the post-school experience of secondary school leavers who left school in the period 1973–1977.Some aspects of these surveys are discussed in this article which covers the experience of school leavers in finding out about jobs and training, waiting time for jobs, and estimates of unemployment. The occupations entered by school leavers are then assessed in relation to demand projections for educated manpower.These observations reveal that institutional arrangements for transferring school leavers from school to work are embryonic and for a large minority of leavers family and other influentiaal contacts are more important than qualifications in securing a job. For Form 3 Junior Secondary School leavers some credence may be given to the popular impression that unemployment is worsening but Form 5 High School leavers are experiencing little difficulty as yet in finding work. More tentatively it would appear that the marginal additions to the skilled labour force stemming from school leavers are not modifying the occupational structure in line with recent manpower projections.  相似文献   
189.
The article provides a factual account of the present organisation and structure of teacher training in the Netherlands and outlines the content of training for intending teachers of modern languages. Plans for innovation are also discussed.  相似文献   
190.
The influence of solvent (in its gaseous state) on the stability of crystallized organic compounds was investigated. Through two examples of studies on the solid/vapour equilibria made in our lab, several behaviors were highlighted: (i) a new hydrated phase (thermodynamically stable) of an active pharmaceutical ingredient (API) was detected after the recrystallization starting from a deliquescent state, (ii) a spontaneous resolution of a hydrated racemic compound towards an anhydrous conglomerate can occur during the desolvation under the precise conditions of temperature and humidity. This study illustrates that knowledge about solid/vapour equilibrium is a crucial step during the complete characterization of solid organic compounds.  相似文献   
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