全文获取类型
收费全文 | 11543篇 |
免费 | 123篇 |
国内免费 | 9篇 |
专业分类
教育 | 8760篇 |
科学研究 | 773篇 |
各国文化 | 189篇 |
体育 | 652篇 |
综合类 | 6篇 |
文化理论 | 116篇 |
信息传播 | 1179篇 |
出版年
2021年 | 100篇 |
2020年 | 130篇 |
2019年 | 233篇 |
2018年 | 302篇 |
2017年 | 347篇 |
2016年 | 329篇 |
2015年 | 247篇 |
2014年 | 322篇 |
2013年 | 2636篇 |
2012年 | 258篇 |
2011年 | 280篇 |
2010年 | 253篇 |
2009年 | 248篇 |
2008年 | 290篇 |
2007年 | 284篇 |
2006年 | 241篇 |
2005年 | 265篇 |
2004年 | 260篇 |
2003年 | 215篇 |
2002年 | 191篇 |
2001年 | 169篇 |
2000年 | 175篇 |
1999年 | 182篇 |
1998年 | 147篇 |
1997年 | 154篇 |
1996年 | 164篇 |
1995年 | 179篇 |
1994年 | 162篇 |
1993年 | 139篇 |
1992年 | 157篇 |
1991年 | 138篇 |
1990年 | 131篇 |
1989年 | 122篇 |
1988年 | 115篇 |
1987年 | 109篇 |
1986年 | 104篇 |
1985年 | 116篇 |
1984年 | 122篇 |
1983年 | 116篇 |
1982年 | 122篇 |
1981年 | 99篇 |
1980年 | 75篇 |
1979年 | 85篇 |
1978年 | 89篇 |
1977年 | 92篇 |
1976年 | 76篇 |
1975年 | 64篇 |
1974年 | 66篇 |
1973年 | 62篇 |
1971年 | 52篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
The purposes of this study were to determine the relationships between: (a) measures of body size/composition and heat production/storage, and (b) heat production/storage and heart rate (HR) drift during running at 95% of the velocity that elicited lactate threshold, which was determined for 20 healthy recreational male runners. Subsequently, changes in skin and tympanic temperatures associated with a vigorous 20-min run, HR, and VO2 data were recorded. It was found that heat production was significantly correlated with body mass (r = .687), lean mass (r = .749), and body surface area (BSA, r = .699). Heat storage was significantly correlated with body mass (r = .519), fat mass (r = .464), and BSA (r = .498). The percentage of produced heat stored was significantly correlated with body mass (r = .427), fat mass (r = .455), and BSA (r = .414). Regression analysis showed that the sum of body mass, percentage of body fat, BSA, lean mass, and fat mass accounted for 30% of the variability in heat storage. It was also found that HR drift was significantly correlated with heat storage (r = .383), percentage of produced heat stored (r = .433), and core temperature change (r = .450). It was concluded that heavier runners experienced greater heat production, heat storage, and core temperature increases than lighter runners during vigorous running. 相似文献
992.
Ring C Carroll D Hoving J Ormerod J Harrison LK Drayson M 《Journal of sports sciences》2005,23(5):501-508
It has been suggested that the psychological stress associated with competitive sports events may help to explain the increased susceptibility to respiratory infections due to reductions in secretory immunity. In the current study, we investigated the influence of competitive exercise and psychological stress on secretory immunoglobulin A (s-IgA). Salivary s-IgA and heart rate were measured in 62 healthy young recreationally active men at rest and, in a between-subjects design, following one of four 8-min tasks: mental arithmetic, cycling at workloads of 60 to 180 W (mean = 146 W), mental arithmetic while cycling, or competitive cycling. Mental arithmetic was associated with significant increases in s-IgA concentration (mean = 49 microg.min(-1)) and s-IgA secretion rate (mean = 25 microg.ml(-1)) compared with rest, while mental arithmetic combined with exercise was associated with a significant increase in s-IgA concentration only (mean = 124 microg.min(-1)). In contrast, competitive exercise and exercise alone did not influence s-IgA concentration or secretion rate. Heart rate increased modestly to mental arithmetic (mean = 7 beats.min(-1)) and substantially, and similarly, to the three exercise tasks (mean = 56(62 beats.min(-1)). The hypothesis that the psychological stress of competitive exercise contributes to increased susceptibility to infection via reductions in s-IgA requires further investigation. 相似文献
993.
994.
995.
996.
Faculty uses of doctoral training: Consideration of a technique for the differentiation of scholarly effort from research activity 总被引:1,自引:1,他引:0
The purposes of this study are: (1) to differentiate scholarly effort from research activity, and (2) to test the notion that publications are a discrete measure of scholarly performance. Validity was established for 71 scholarly activities apart from publications; these were classified into two domains: the external-disciplinary colleague (EDC) and the institutional local-community (ILC). A mailed survey of a sample of PhD recipients in chemistry and psychology at 44 liberal arts colleges—Selectivity I yielded a 63% useable return on 186 respondents. High and low publishers (career and current) were compared on both EDC and ILC Domain performance. Findings were that high publishers (career and current) have higher levels of performance in both Domains than do low publishers (career and current).An earlier version of this paper was presented at the twentieth Annual Forum of the Association for Institutional Research, Atlanta, April 1980. 相似文献
997.
998.
999.
1000.