首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   5490篇
  免费   142篇
  国内免费   157篇
教育   790篇
科学研究   104篇
体育   3632篇
综合类   1258篇
信息传播   5篇
  2022年   32篇
  2021年   82篇
  2020年   121篇
  2019年   65篇
  2018年   98篇
  2017年   106篇
  2016年   122篇
  2015年   125篇
  2014年   234篇
  2013年   511篇
  2012年   332篇
  2011年   393篇
  2010年   269篇
  2009年   265篇
  2008年   297篇
  2007年   410篇
  2006年   371篇
  2005年   341篇
  2004年   349篇
  2003年   279篇
  2002年   238篇
  2001年   221篇
  2000年   169篇
  1999年   98篇
  1998年   74篇
  1997年   59篇
  1996年   32篇
  1995年   30篇
  1994年   19篇
  1993年   23篇
  1992年   13篇
  1991年   6篇
  1990年   4篇
  1989年   1篇
排序方式: 共有5789条查询结果,搜索用时 31 毫秒
991.
Purpose: The purpose of this study was to examine the association between objectively measured physical activity and hearing sensitivity among a nationally representative sample of U.S. adults with diabetes. Method: Data from the 2003–2006 National Health and Nutrition Examination Survey were used. One hundred eighty-four U.S. adults with diabetes wore an ActiGraph 7164 accelerometer and had their hearing function objectively assessed. A negative binomial logistic regression was used to examine the association between moderate-to-vigorous physical activity (MVPA) and hearing sensitivity. Results were adjusted for age, gender, race/ethnicity, education, body mass index, comorbidity index, marital status, cotinine, homocysteine, high-density lipoprotein cholesterol, glycohemoglobin (HbA1c), C-reactive protein, microalbuminuria, noise exposure, and vision impairment. Results: Compared to those with hearing within normal limits, results showed that participants with mild hearing loss and moderate or greater hearing loss, respectively, engaged in 93% fewer minutes of MVPA (incident rate ratio = 0.07; 95% CI [0.01, 0.60]) and 94% fewer minutes of MVPA (incident rate ratio = 0.06; 95% CI [0.01, 0.54]). Conclusion: Adults with diabetes who have greater hearing impairment are less physically active. Future research is needed to determine the direction of causality.  相似文献   
992.
The purpose of this study was to determine if a difference in interleukin-6 (IL-6) and delayed onset muscles soreness (DOMS) exists in two different phases of the menstrual cycle. Nine runners performed one 75-min high-intensity interval running session during the early follicular (EF) phase and once during the midluteal (ML) phase of the menstrual cycle. Estrogen and progesterone levels were significantly reduced in the EF phase when compared to the ML phase. IL-6 levels increased from pre- to postexercise in the EF and ML phases (p < .001). There was no relationship between the IL-6 level and DOMS. The results suggest that menstruating female runners need not vary training throughout the month to reduce DOMS.  相似文献   
993.
Previous analyses (i.e., Bernstein & St. John, 2006; Sender & Sullivan, 2008) of the television show The Biggest Loser have detailed its negative presentation of the obese body, potential consequences for viewers, and its role as a technology of governmentality. However, there has been little exploration of how audience members conceptualize and enact the messages communicated in the show within these intricate frameworks. The current research used information from semistructured interviews with 40 dedicated viewers to capture the salient meanings they ascribed to The Biggest Loser within the themes of governmentality and self-concept. Overall, the group experienced the program as a transformative, entertaining, and inspirational event that produced little change in their exercise behavior. Thus, the role of reality television in creating healthy behavior change is potentially limited.  相似文献   
994.
995.
996.
The physiology research at the Royal Central Institute of Gymnastics (Swedish acronym: GCI) in Stockholm was never primarily focused on sports, but has made significant contributions to sport and exercise physiology. Changing ideas about the human body (from form to motor) during the early twentieth century led to criticism towards the posture-oriented Ling gymnastics. The rationalisation movement of the 1930s and onwards also paved the way for a rationalistic physiology research. GCI recruited Eric Hohwü Christensen (1904–1996) from Copenhagen for the new position as professor in physiology in 1941. Christensen built his research programme on the ideas of the Copenhagen School, focusing on basic research, bodily limits and rationalisation of exercise. The majority of research at GCI focused on basic physiology, and the main goal was to rationalise the exercise of the entire population, which was in line with the ambitions of the emerging Swedish welfare state. But applications in elite sports became a claim to fame for GCI through names such as Per-Olof Åstrand and Bengt Saltin. This article aims at showing how the research programme was outlined during Christensen's professorship, 1941–1969. How does a scientific environment focused on basic, physiological research become famous for its impact in sports?  相似文献   
997.
Abstract

Nine males cycled at 53% (s = 2) of their peak oxygen uptake ([Vdot]O2peak) for 90 min (dry bulb temperature: 25.4°C, s = 0.2; relative humidity: 61%, s = 3). One litre of flavoured water at 10 (cold), 37 (warm) or 50°C (hot) was ingested 30 – 40 min into exercise. Immediately after the 90 min of exercise, participants cycled at 95%[Vdot]O2peak to exhaustion to assess exercise capacity. Rectal and mean skin temperatures and heart rate were recorded. The gradient of rise in rectal temperature was influenced (P < 0.01) by drink temperature. Mean skin temperature was highest in the hot trial (cold trial: 34.2°C, s = 0.5; warm trial: 34.4°C, s = 0.5; hot trial: 34.7°C, s = 0.6; P < 0.01). Significant differences were observed in heart rate (cold trial: 132 beats · min?1, s = 13; warm trial: 134 beats · min?1, s = 12; hot trial: 139 beats · min?1, s = 13; P < 0.05). Exercise capacity was similar between trials (cold trial: 234 s, s = 69; warm trial: 214 s, s = 52; hot trial: 203 s, s = 53; P = 0.562). The heat load and debt induced via drinking resulted in appropriate thermoregulatory reflexes during exercise leading to an observed heat content difference of only 33 kJ instead of the predicted 167 kJ between the cold and hot trials. These results suggest that there may be a role for drink temperature in influencing thermoregulation during exercise.  相似文献   
998.
Abstract

Energy turnover was assessed in two conditions of mixed ultra-endurance exercise. In Study 1, energy expenditure and intake were measured in nine males in a laboratory over 24 h. In Study 2, energy expenditure was assessed in six males during an 800-km Adventure race (mean race time 152.5 h). Individual correlations between heart rate and oxygen uptake ([Vdot]O2) were established during pre-tests when kayaking, cycling, and running. During exercise, energy expenditure was estimated from continuous heart rate recordings. Heart rate and [Vdot]O2 were measured regularly during fixed cycling work rates to correct energy expenditure for drift in oxygen pulse. Mean energy expenditure was 18,050 ± 2,390 kcal (750 ± 100 kcal · h?1) and 80,000 ± 18,000 kcal (500 ± 100 kcal · h?1) in Study 1 and Study 2 respectively, which is higher than previously reported. Energy intake in Study 1 was 8,450 ± 1,160 kcal, resulting in an energy deficit of 9,590 ± 770 kcal. Body mass decreased in Study 1 (?2.3 ± 0.8 kg) but was unchanged in Study 2. Fat mass decreased in Study 2 (?2.3 ± 1.5 kg). In Study 1, muscle glycogen content decreased by only 60%. Adventure racing requires a high energy expenditure, with large inter-individual variation. A large energy deficit is caused by inadequate energy intake, possibly due to suppressed appetite and gastrointestinal problems. The oxygen pulse, comparing start to 12 h of exercise and beyond, increased by 10% and 5% in Study 1 and Study 2 respectively. Hence, estimations of energy expenditure from heart rate recordings should be corrected according to this drift.  相似文献   
999.
Abstract

The aim of this study was to determine whether rates of total fat and carbohydrate oxidation and endurance capacity during running conducted in the fasted state are influenced by the glycaemic index (GI) of high carbohydrate diets consumed over 5 days. Nine healthy males performed three treadmill runs to exhaustion at 65% of maximum oxygen uptake ([Vdot]O2max): after a habitual diet (control trial), after 5 days on a high carbohydrate/high glycaemic index diet, and after 5 days on a high carbohydrate/low glycaemic index diet in randomized counterbalanced order. No significant differences in rates of fat and carbohydrate oxidation, concentrations of plasma insulin, glucose, non-esterified fatty acids and glycerol, or time to exhaustion were observed between the high carbohydrate/high glycaemic index and high carbohydrate/low glycaemic index trials. Compared with the control trial, the concentration of plasma glycerol and rate of fat oxidation were lower (P < 0.05) and the rate of carbohydrate oxidation higher (P < 0.05) in both the high carbohydrate/high glycaemic index diet and high carbohydrate/low glycaemic index trials during the run to exhaustion. In conclusion, the extent by which a high carbohydrate diet consumed over 5 days reduces rate of fat oxidation during subsequent running exercise in the fasted state is not influenced by the glycaemic index of the diet.  相似文献   
1000.
Abstract

Thirty-six male rats were used; divided into 6 groups (n = 6): saline; creatine (Cr); eccentric exercise (EE) plus saline 24 h (saline + 24 h); eccentric exercise plus Cr 24 h (Cr + 24 h); eccentric exercise plus saline 48 h (saline + 48 h); and eccentric exercise plus Cr 48 h (Cr + 48h). Cr supplementation was administered as a solution of 300 mg · kg body weight?1 · day?1 in 1 mL water, for two weeks, before the eccentric exercise. The animals were submitted to one downhill run session at 1.0 km · h?1 until exhaustion. Twenty-four and forty-eight hours after the exercise, the animals were killed, and the quadriceps were removed. Creatine kinase levels, superoxide production, thiobarbituric acid reactive substances (TBARS) level, carbonyl content, total thiol content, superoxide dismutase, catalase, glutathione peroxidase, interleukin-1b (IL-1β), nuclear factor kappa B (NF-kb), and tumour necrosis factor (TNF) were analysed. Cr supplementation neither decreases Cr kinase, superoxide production, lipoperoxidation, carbonylation, total thiol, IL-1β, NF-kb, or TNF nor alters the enzyme activity of superoxide dismutase, catalase, and glutathione peroxides in relation to the saline group, respectively (P < 0.05). There are positive correlations between Cr kinase and TBARS and TNF-α 48 hours after eccentric exercise. The present study suggests that Cr supplementation does not decrease oxidative stress and inflammation after eccentric contraction.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号