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41.
42.
Abstract

In this holistic review of cycling science, the objectives are: (1) to identify the various human and environmental factors that influence cycling power output and velocity; (2) to discuss, with the aid of a schematic model, the often complex interrelationships between these factors; and (3) to suggest future directions for research to help clarify how cycling performance can be optimized, given different race disciplines, environments and riders. Most successful cyclists, irrespective of the race discipline, have a high maximal aerobic power output measured from an incremental test, and an ability to work at relatively high power outputs for long periods. The relationship between these characteristics and inherent physiological factors such as muscle capilliarization and muscle fibre type is complicated by inter-individual differences in selecting cadence for different race conditions. More research is needed on high-class professional riders, since they probably represent the pinnacle of natural selection for, and physiological adaptation to, endurance exercise. Recent advances in mathematical modelling and bicycle-mounted strain gauges, which can measure power directly in races, are starting to help unravel the interrelationships between the various resistive forces on the bicycle (e.g. air and rolling resistance, gravity). Interventions on rider position to optimize aerodynamics should also consider the impact on power output of the rider. All-terrain bicycle (ATB) racing is a neglected discipline in terms of the characterization of power outputs in race conditions and the modelling of the effects of the different design of bicycle frame and components on the magnitude of resistive forces. A direct application of mathematical models of cycling velocity has been in identifying optimal pacing strategies for different race conditions. Such data should, nevertheless, be considered alongside physiological optimization of power output in a race. An even distribution of power output is both physiologically and biophysically optimal for longer ( >4km) time-trials held in conditions of unvarying wind and gradient. For shorter races (e.g. a 1km time-trial), an‘all out’ effort from the start is advised to‘save’ time during the initial phase that contributes most to total race time and to optimize the contribution of kinetic energy to race velocity. From a biophysical standpoint, the optimum pacing strategy for road time-trials may involve increasing power in headwinds and uphill sections and decreasing power in tailwinds and when travelling downhill. More research, using models and direct power measurement, is needed to elucidate fully how much such a pacing strategy might save time in a real race and how much a variable power output can be tolerated by a rider. The cyclist's diet is a multifactorial issue in itself and many researchers have tried to examine aspects of cycling nutrition (e.g. timing, amount, composition) in isolation. Only recently have researchers attempted to analyse interrelationships between dietary factors (e.g. the link between pre-race and in-race dietary effects on performance). The thermal environment is a mediating factor in choice of diet, since there may be competing interests of replacing lost fluid and depleted glycogen during and after a race. Given the prevalence of stage racing in professional cycling, more research into the influence of nutrition on repeated bouts of exercise performance and training is required.  相似文献   
43.
Two strains of rats (albino Wistar and hooded PVG/c) were exposed to a conditioned defensive burying paradigm that consisted of placing rats in a test chamber with bedding material on the floor, shocking them with a shock prod, and recording the time each rat spent in burying responses toward the prod. Various behaviors other than burying (freezing, grooming/paw licking) were observed by a time-sampling procedure during the control, conditioning, and extinction sessions, each of which was 15 min in duration. Wistar rats generally showed behavioral inhibition, as evidenced by less burying, lower exploratory and ambulatory behavior, and higher freezing behavior. PVG/c rats spent significantly more time engaged in burying and accumulated more bedding material in the conditioning session than did the Wistar rats. No significant differences between the two strains of rats were observed during the extinction session in terms of these measurements. The results indicate that Wistar rats have a greater tendency to freeze when coping with the noxious stimulus in a conditioned defensive burying paradigm, whereas the dominant coping style for PVG/c rats is defensive burying.  相似文献   
44.
Teaching has been described as an emerging community of practice. Within such professional communities, the processes of reflection and collaborative dialogue, or critical transformative dialogue, are central to the maintenance and improvement of professional practice for individuals, and the field. This paper reports on the challenges experienced by a group of first-year pre-service teachers engaging in a process of reflection and critique with peers, as they participated in a program focused on the development of core practices of teaching. These pre-service teachers' responses indicated their growing understanding of the importance of engaging in ongoing critical dialogue, as part of the “unnatural” aspects of teaching. The paper concludes with a reflection on the value of feedback from the earliest stages of professional learning.  相似文献   
45.
This article engages with methodological concerns connected to insider education research and the ‘race-symmetry’ shared between the researcher and teacher participants. To do this, race critical reflexive strategies are utilized to show how and why this practice productively contributed to the knowledge about race making constructed in my study, a research process I describe as getting inside my insiderness. However, these reflexive practices also helped me to develop a deeper awareness of the potential for what I now describe as White shadows to infiltrate research of this type. The conceptualization of White shadows is a useful tool to describe research practices that silence or deflect attention away from issues connected to race, and hence, White shadows help expose concerns about the potential for Whiteness to remain protected by research. There are two interconnected aims of this paper. First, to illustrate the sort of race reflexive practices called for, and in doing so, to demonstrate why they are valuable and helpful in (educational) research. Second, I hope to encourage a rethink of the insider–outsider relationship that typifies ethnographic research by shifting attention to explore the inside of insider research.  相似文献   
46.
This study reports on the composing process of one student, Peta (a pseudonym), as he reflects on a significant composition he produced during a unit on identity in a 12th‐grade English class in a U. S. high school. The unit was the first thematic exploration of the year for the students and was designed to help them think about themselves as readers, writers, and individuals. The teacher's goal was to have students' engagements with literary and artistic texts serve as vehicles for developing better understandings of themselves. The study demonstrates how students' engagement with more ‘traditional’ artefacts is essentially an example of multimodality and evidences why teachers and researchers should see such work as part of the long tradition of creativity within English. It also demonstrates how such an apparently ‘traditional’ artistic approach in fact covers the same territory as that of the digital revolution, that is that multimodal ‘tools’ engage all the cultural resources of students from their domestic, community and school settings, in contrast with much typical school activity that is perceived as pointless and tedious.  相似文献   
47.
Australian universities over the last 25 years have been unified, internationalised, corporatised and become mass educational providers. This process is replicated globally as a response to rapid mass enrolments and marketisation. In the light of these changes, a corporate and managerial model has been identified, which has been the subject of growing discontent within the academic workforce. However, from a political economy perspective there is a lack of understanding on how and by what means academic labour has been commodified in this process. This paper, using Australia as its case study, argues that the managerial culture has alienated academics from their labour. This has resulted in them losing control over their skills and thus becoming disassociated from the educational purposes of their work. Higher education has been subjected to systemic regulatory governance that has fundamentally transformed the nature of academic labour. We contend that the regulatory state has reached so deep down into the university that academics have effectively become a de-professionalised and proletarianised labour force.  相似文献   
48.
In this study, we investigated the effects of two hydrotherapy interventions on match running performance and perceptual measures of fatigue and recovery during a 4-day soccer tournament. Twenty male junior soccer players were assigned to one of two treatment groups and undertook either cold-water immersion (5 × 1 min at 10 °C) or thermoneutral water immersion (5 × 1 min at 34 °C) after each match. High-intensity running distance (>15 km · h?1) and total distance covered, time spent in low (<80% maximum heart rate), moderate (80-90% maximum heart rate), and high (>90% maximum heart rate) heart rate zones, and rating of perceived exertion (RPE) were recorded for each match. Perceptions of general fatigue and leg soreness were recorded approximately 22 h after each match. There were decreases in both groups across the 4-day tournament for high-intensity running distance (P = 0.006, Cohen's d = 0.63), total distance run (P < 0.001, d = 0.90), time in high heart rate zone (P = 0.003, d = 0.90), and match RPE (P = 0.012, d = 0.52). Cold-water immersion was more effective than thermoneutral immersion for reducing the perception of leg soreness (P = 0.004, d = -0.92) and general fatigue (P = 0.007, d = -0.91), ameliorating the decrement in total distance run (P = 0.001, d = 0.55), and maintaining time in the moderate heart rate zone (P = 0.01, d = 1.06). In conclusion, cold-water immersion mediates the perceptions of fatigue and recovery and enhances the restoration of some match-related performance measures during a 4-day tournament.  相似文献   
49.
In this paper, four teachers shared their experiences using the following free Web 2.0 tools with their students: Jing, Wix, Google Sites, and Blogger. The teachers found that students reacted positively to lessons in which these tools were used, and also noted improvements they could make when using them in the future.  相似文献   
50.

Objective

(1) To describe lacerations of the vaginal fornices, an injury known to be associated with consensual sexual intercourse, including known complications and treatment course, (2) to contrast these injuries with injuries sustained during sexual assault, and (3) to discuss the assessment of adolescent patients for sexual injuries.

Methods

We present a case series of 4 female adolescent patients seen at a children's hospital over a period of 6 months. Each patient developed significant vaginal bleeding after sexual intercourse, and 3 of the patients presented to the emergency department with vital signs consistent with compensated shock.

Results

Each patient was evaluated by pediatric surgery, and found to have a laceration of the vagina. Three of the patients described consensual intercourse prior to the onset of bleeding, and had lacerations of the vaginal fornices; these patients were determined to have injuries resulting from consensual sexual intercourse. The fourth patient reported sexual assault as the cause of her injuries, and was treated for longitudinal lacerations of the vaginal wall.

Conclusions

Lacerations of the upper vagina are not frequently reported in forced vaginal intercourse, but are occasionally reported as injuries sustained during consensual coitus. In the absence of reported sexual assault, a severe vaginal fornix laceration is consistent with the diagnosis of coital injury from consensual intercourse. Diagnosis and treatment of this injury can be delayed due to the sensitive nature of these injuries. Bleeding can be profuse, leading to hemorrhagic shock, and these injuries may require transfusion of blood products and surgical repair in some cases. Complications may include hemoperitoneum, pneumoperitoneum, or retroperitoneal hematoma, even in the absence of complete vaginal perforation.

Practice implications

Knowledge of the consensual sexual injuries that may occur in adolescent patients can guide diagnosis, treatment, and counseling for the patient and her family, preventing long-term medical complications and legal consequences.  相似文献   
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