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   3971篇
  免费   64篇
  国内免费   4篇
教育   2914篇
科学研究   271篇
各国文化   70篇
体育   360篇
综合类   1篇
文化理论   37篇
信息传播   386篇
  2023年   14篇
  2022年   21篇
  2021年   42篇
  2020年   69篇
  2019年   115篇
  2018年   139篇
  2017年   154篇
  2016年   133篇
  2015年   92篇
  2014年   127篇
  2013年   914篇
  2012年   117篇
  2011年   101篇
  2010年   86篇
  2009年   101篇
  2008年   122篇
  2007年   113篇
  2006年   104篇
  2005年   100篇
  2004年   90篇
  2003年   75篇
  2002年   78篇
  2001年   52篇
  2000年   62篇
  1999年   62篇
  1998年   45篇
  1997年   44篇
  1996年   61篇
  1995年   47篇
  1994年   51篇
  1993年   34篇
  1992年   51篇
  1991年   36篇
  1990年   44篇
  1989年   36篇
  1988年   29篇
  1987年   24篇
  1986年   27篇
  1985年   23篇
  1984年   21篇
  1983年   15篇
  1982年   24篇
  1981年   29篇
  1980年   27篇
  1979年   18篇
  1978年   21篇
  1976年   19篇
  1975年   14篇
  1974年   20篇
  1973年   15篇
排序方式: 共有4039条查询结果,搜索用时 15 毫秒
131.
Objective:We recently showed that the gender detection tools NamSor, Gender API, and Wiki-Gendersort accurately predicted the gender of individuals with Western given names. Here, we aimed to evaluate the performance of these tools with Chinese given names in Pinyin format.Methods:We constructed two datasets for the purpose of the study. File #1 was created by randomly drawing 20,000 names from a gender-labeled database of 52,414 Chinese given names in Pinyin format. File #2, which contained 9,077 names, was created by removing from File #1 all unisex names that we were able to identify (i.e., those that were listed in the database as both male and female names). We recorded for both files the number of correct classifications (correct gender assigned to a name), misclassifications (wrong gender assigned to a name), and nonclassifications (no gender assigned). We then calculated the proportion of misclassifications and nonclassifications (errorCoded).Results:For File #1, errorCoded was 53% for NamSor, 65% for Gender API, and 90% for Wiki-Gendersort. For File #2, errorCoded was 43% for NamSor, 66% for Gender API, and 94% for Wiki-Gendersort.Conclusion:We found that all three gender detection tools inaccurately predicted the gender of individuals with Chinese given names in Pinyin format and therefore should not be used in this population.  相似文献   
132.
133.
In this study, we examined the effects of different work:rest durations during 20 min intermittent treadmill running and subsequent performance. Nine males (mean age 25.8 years, s = 6.8; body mass 73.9 kg, s = 8.8; stature 1.75 m, s = 0.05; VO(2max) 55.5 ml x kg(-1) x min(-1), s = 5.8) undertook repeated sprints at 120% of the speed at which VO(2max) was attained interspersed with passive recovery. The work:rest ratio was constant (1:1.5) with trials involving either short (6:9 s) or long (24:36 s) work:rest exercise protocols (total exercise time 8 min). Each trial was followed by a performance run to volitional exhaustion at the same running speed. Testing order was randomized and counterbalanced. Heart rate, oxygen consumption, respiratory exchange ratio, and blood glucose were similar between trials (P > 0.05). Blood lactate concentration was greater during the long than the short exercise protocol (P < 0.05), whereas blood pH was lower during the long than the short exercise protocol (7.28, s = 0.11 and 7.30, s = 0.03 at 20 min, respectively; P < 0.05). Perceptions of effort were greater throughout exercise for the long than the short exercise protocol (16.6, s = 1.4 and 15.1, s = 1.6 at 20 min, respectively; P < 0.05) and correlated with blood lactate (r = 0.43) and bicarbonate concentrations (r = 0.59; P < 0.05). Although blood lactate concentration at 20 min was related to performance time (r = - 0.56; P < 0.05), no differences were observed between trials for time to exhaustion (short exercise protocol: 95.8 s, s = 30.0; long exercise protocol: 92.0 s, s = 37.1) or physiological responses at exhaustion (P > 0.05). Our results demonstrate that 20 min of intermittent exercise involving a long work:rest duration elicits greater metabolic and perceptual strain than intermittent exercise undertaken with a short work:rest duration but does not affect subsequent run time to exhaustion.  相似文献   
134.
The purpose of this study was to compare submaximal physiological responses and indices of mechanical efficiency between asynchronous and synchronous arm ergometry. Thirteen wheelchair-dependent trained athletes performed eight steady-state incremental bouts of exercise (0 to 140 W), each lasting 4 min, using synchronous and asynchronous arm-cranking strategies. Physiological measures included oxygen uptake (VO2), heart rate, and blood lactate concentration. The power outputs corresponding to fixed whole blood lactate concentrations of 2.0 to 4.0 mmol x l(-1) were calculated using linear interpolation. Mechanical efficiency indices - gross efficiency, net efficiency, and work efficiency - were also calculated. An analysis of variance with repeated measures was applied to determine the effect of crank mode on the physiological parameters. Oxygen uptake was on average 10% lower (P < 0.01), and both net efficiency (P < 0.01) and gross efficiency (P < 0.01) were higher, during the asynchronous strategy at both 60 and 80 W (gross efficiency: 16.9 +/- 2.0% vs. 14.7 +/- 2.4% and 17.5 +/- 1.8% vs. 15.9 +/- 2.6% at 60 and 80 W respectively). There were no differences in heart rate, blood lactate concentration or power output at either of the blood lactate reference points between the asynchronous and synchronous strategies (P > 0.05). In conclusion, test specificity is an important consideration. If a synchronous strategy is to be adopted, it is likely to result in lower efficiency than an asynchronous strategy. The exercise testing scenario may help dictate which method is ultimately chosen.  相似文献   
135.
To determine gender differences, positional differences, and patterns of change in the performance of the basketball line-drill test, 93 male (mean age 16.8 years, s = 1.1) and 95 female (mean age 16.5 years, s = 1.0) basketball players undertook 516 line-drill tests over a 5-year period. Log-transformed performance times were analysed using a mixed model that included quadratic within-participant fixed effects for time in the season and time in the programme. Changes and differences were standardized for interpretation of magnitudes. Mean performance times were 28.0 s (s = 1.3) for males and 30.4 s (s = 1.3) for females. The mean pattern of change in performance within a season differed substantially between the sexes and playing positions: male guards and female centres showed moderate to very large improvements mid-season of 1.1% and 3.5% respectively (90% confidence limits +/-2.1% and +/-3.0%), while female guards and male forwards showed large to very large decrements of -1.6% (+/-2.6%) and -2.4% (+/-2.0%). Over 3 years, males improved performance across all three playing positions by 1.4% (+/-1.3%) and females by 2.9% (+/-1.4%). Males improved performance by 0.2% (+/-0.5%) per year, whereas the performance of females deteriorated by 0.6% (+/-0.4%) per year. The differing patterns of performance change presumably reflect variations in training and competition loads, with short-term fluctuations in performance being managed to promote longer-term improvements.  相似文献   
136.
137.
138.
139.
Broader contextual factors that influence concussion management have tended to be overlooked. To address this, the present study used a sociotechnical systems approach to identify perceived responsibilities and applied strategies for three domains of concussion management (i.e., prevention, identification and treatment). Participants were 118 members of the community rugby union system in Australia (69.2% male). Participants from throughout the rugby system (e.g., players, parents, coaches, club management) were asked open-ended questions about their perceived responsibilities and the strategies they use for concussion management. It was found that (a) proper training, technique correction and education were recurrent prevention themes; (b) the majority of key stakeholders felt that they could consistently identify concussion; however, medical aids (medics) were the only system actors who stated a responsibility to use standardised concussion assessment measures and (c) less than one third of the respondents indicated their involvement in treating concussion. This study identifies specific junctures in the system that prevents effective concussion management strategies. A sociotechnical systems approach improves the understanding of concussion prevention, and management beliefs and behaviours.  相似文献   
140.
ABSTRACT

The purpose of the study was to assess the validity and inter-bike reliability of 10 Wattbike cycle ergometers, and to assess the test–retest reliability of one Wattbike. Power outputs from 100 to 1000 W were applied using a motorised calibration rig (LODE) at cadences of 70, 90, 110 and 130 rev · min?1, which created nineteen different intensities for comparison. Significant relationships (P < 0.01, r2 = 0.99) were found between each of the Wattbikes and the LODE. Each Wattbike was found to be valid and reliable and had good inter-bike agreement. Within-bike mean differences ranged from 0.0 W to 8.1 W at 300 W and 3.3 W to 19.3 W at 600 W. When taking into account the manufacturers stated measurement error for the LODE (2%), the mean differences were less than 2%. Comparisons between Wattbikes at each of the nineteen intensities gave differences from 0.6 to 25.5 W at intensities of 152 W and 983 W, respectively. There was no significant difference (P > 0.05) between the measures of power recorded in the test–retest condition. The data suggest that the Wattbike is an accurate and reliable tool for training and performance assessments, with data between Wattbikes being able to be used interchangeably.  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