全文获取类型
收费全文 | 23500篇 |
免费 | 281篇 |
国内免费 | 14篇 |
专业分类
教育 | 16697篇 |
科学研究 | 1920篇 |
各国文化 | 250篇 |
体育 | 2293篇 |
综合类 | 7篇 |
文化理论 | 212篇 |
信息传播 | 2416篇 |
出版年
2021年 | 235篇 |
2020年 | 359篇 |
2019年 | 536篇 |
2018年 | 728篇 |
2017年 | 665篇 |
2016年 | 662篇 |
2015年 | 402篇 |
2014年 | 532篇 |
2013年 | 4233篇 |
2012年 | 484篇 |
2011年 | 536篇 |
2010年 | 402篇 |
2009年 | 435篇 |
2008年 | 473篇 |
2007年 | 439篇 |
2006年 | 415篇 |
2005年 | 358篇 |
2004年 | 389篇 |
2003年 | 304篇 |
2002年 | 323篇 |
2001年 | 458篇 |
2000年 | 508篇 |
1999年 | 434篇 |
1998年 | 255篇 |
1997年 | 248篇 |
1996年 | 306篇 |
1995年 | 244篇 |
1994年 | 257篇 |
1993年 | 220篇 |
1992年 | 349篇 |
1991年 | 366篇 |
1990年 | 339篇 |
1989年 | 364篇 |
1988年 | 336篇 |
1987年 | 325篇 |
1986年 | 325篇 |
1985年 | 370篇 |
1984年 | 292篇 |
1983年 | 303篇 |
1982年 | 239篇 |
1981年 | 246篇 |
1980年 | 259篇 |
1979年 | 349篇 |
1978年 | 258篇 |
1977年 | 238篇 |
1976年 | 199篇 |
1975年 | 181篇 |
1974年 | 182篇 |
1973年 | 176篇 |
1971年 | 174篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
891.
892.
893.
The effects of training with overweight and underweight cricket balls on fast-bowling speed and accuracy were investigated in senior club cricket bowlers randomly assigned to either a traditional (n = 9) or modified-implement training (n = 7) group. Both groups performed bowling training three times a week for 10 weeks. The traditional training group bowled only regulation cricket balls (156 g), whereas the modified-implement training group bowled a combination of overweight (161-181 g), underweight (151-131 g) and regulation cricket balls. A radar gun measured the speed of 18 consecutive deliveries for each bowler before, during and after the training period. Video recordings of the deliveries were also analysed to determine bowling accuracy in terms of first-bounce distance from the stumps. Bowling speed, which was initially 108 +/- 5 km h(-1) (mean +/- standard deviation), increased in the modified-implement training group by 4.0 km x h(-1) and in the traditional training group by 1.3 km x h(-1) (difference, 2.7 km x h(-1); 90% confidence limits, 1.2 to 4.2 km x h(-1)). For a minimum worthwhile change of 5 km x h(-1), the chances that the true effect on bowling speed was practically beneficial/trivial/harmful were 1.0/99/< 0.1%. For bowling accuracy, the chances were 1/48/51%. This modified-implement training programme is not a useful training strategy for club cricketers. 相似文献
894.
International travel is an essential part of the life of elite athletes, both for competition and training. It is also becoming increasingly common among recreational sportspersons. Long-distance travel is associated with a group of transient negative effects, collectively referred to as 'travel fatigue', which result from anxiety about the journey, the change to an individual's daily routine, and dehydration due to time spent in the dry air of the aircraft cabin. Travel fatigue lasts for only a day or so, but for those who fly across several time zones, there are also the longer-lasting difficulties associated with 'jet lag'. The problems of jet lag can last for over a week if the flight crosses 10 time zones or more, and they can reduce performance and the motivation to train effectively. Knowledge of the properties of the body clock enables the cause of the difficulties to be understood (an unadjusted body clock), and forms the basis of using light in the new time zone to promote adjustment of the body clock. Sleep loss and its effects are important components of jet lag, and attempts to promote sleep by the use of melatonin and other hypnotics are also relevant. Sleep loss is also found in those who undertake challenges that involve long periods where the normal consolidated sleep of 8 h length is not possible. Advice on sleep regimens in such circumstances is given. 相似文献
895.
896.
Schott MJ 《Medical reference services quarterly》2004,23(4):1-11
There have been many recent changes to PubMed to enhance its usefulness. Those changes include: LinkOut Libraries (local holding field), PubMed Central (full-text articles archived by the National Library of Medicine), and LinkOut (access to full-text articles right from the PubMed citation). Medical librarians should be aware of how these features work to best assist their clients. These new features offer the possibility of true desktop access for library patrons. Not only will patrons appreciate these new features, but their use in libraries will literally change what we do, who does it, and how it is done. 相似文献
897.
898.
899.
900.
J. K. PAGE 《Higher Education Quarterly》1964,18(3):301-308