全文获取类型
收费全文 | 649篇 |
免费 | 4篇 |
国内免费 | 3篇 |
专业分类
教育 | 341篇 |
科学研究 | 85篇 |
各国文化 | 8篇 |
体育 | 139篇 |
综合类 | 6篇 |
文化理论 | 2篇 |
信息传播 | 75篇 |
出版年
2023年 | 3篇 |
2022年 | 7篇 |
2021年 | 2篇 |
2018年 | 3篇 |
2016年 | 2篇 |
2015年 | 3篇 |
2014年 | 4篇 |
2013年 | 5篇 |
2012年 | 49篇 |
2011年 | 66篇 |
2010年 | 24篇 |
2009年 | 11篇 |
2008年 | 38篇 |
2007年 | 45篇 |
2006年 | 49篇 |
2005年 | 40篇 |
2004年 | 25篇 |
2003年 | 26篇 |
2002年 | 26篇 |
2001年 | 17篇 |
2000年 | 23篇 |
1999年 | 14篇 |
1998年 | 5篇 |
1997年 | 12篇 |
1996年 | 5篇 |
1995年 | 7篇 |
1994年 | 9篇 |
1993年 | 6篇 |
1992年 | 10篇 |
1991年 | 10篇 |
1990年 | 7篇 |
1989年 | 5篇 |
1988年 | 6篇 |
1987年 | 5篇 |
1986年 | 10篇 |
1985年 | 13篇 |
1984年 | 8篇 |
1983年 | 8篇 |
1982年 | 3篇 |
1981年 | 5篇 |
1980年 | 2篇 |
1979年 | 2篇 |
1958年 | 4篇 |
1944年 | 4篇 |
1937年 | 2篇 |
1934年 | 2篇 |
1933年 | 2篇 |
1929年 | 2篇 |
1928年 | 2篇 |
1905年 | 1篇 |
排序方式: 共有656条查询结果,搜索用时 15 毫秒
81.
Dowda M James F Sallis JF McKenzie TL Rosengard P Kohl HW 《Research quarterly for exercise and sport》2005,76(1):11-19
Dissemination and sustainability of evidence-based physical education programs (PE) has been studied rarely. The sustainability of a health-related PE program (SPARK) was independently evaluated in 111 elementary schools in 7 states. Surveys were mailed to schools that had received SPARK curriculum books, training and follow-up (response rate = 47%). Up to 80% of schools that adopted SPARK PE reported sustained use up to 4 years later. Schools using SPARK had more frequent PE classes. Sustained use was related to support from the principal, not previously having a standard PE program, having adequate equipment, and teachers being physically active. Program sustainability was similar in advantaged and disadvantaged schools. Evidence-based PE programs can be sustained up to 4 years. 相似文献
82.
83.
Hyperthermia can be used as an adjunctive method of chemotherapy, radiotherapy, and gene therapy to improve cancer treatment. In this study, we investigate the hyperthermic cell death of cervix cancer CaSki cells in a microchannel integrated with a directional heating scheme. Heat was applied from the inner end to the outer end of the channel and a temperature distribution from 60 °C to 30 °C was established. A three dimensional (3D) numerical model was conducted for the heat transfer simulation, based on which a simple fitting method was proposed to easily estimate the temperature distribution along the channel. Cell death along the channel was mapped 22 h after the heating treatment by dual fluorescent labeling and phase-contrast microscopy imaging. Upstream, where the temperature is higher than 42 °C, we observe necrotic death, late-stage and early stage apoptotic death in sequence along the channel. Downstream and in the middle of the channel, where the temperature is lower than 42 °C, significant cell detachment was noted. Vigorous detachment was observed even in the non-hyperthermic zone (temperature lower than 37 °C), which we believe is due to the direct effect of the hyperthermic zones (higher than 37 °C). The present work not only gives a vivid map of cell responses under a temperature gradient, but also reveals the potential interactions of the heated tumor cells and non-heated tumor cells, which are seldom investigated in conventional petri-dish experiments. 相似文献
84.
CR Duffy D Stewart F Pecoraro PE Riches D Farina A Macaluso 《Journal of sports sciences》2012,30(12):1311-1321
Abstract To investigate the effects of ageing on the neural control strategies governing sprint cycling on a friction-loaded cycle-ergometer, 10 older (aged 70-83yr) and 8 young (aged 19-35yr) healthy women completed seven 6-s all-out cycling trials against varying loads. Root mean square (RMS), median frequency and muscle fibre conduction velocity were determined from the vastus lateralis of the dominant limb during each pedal stroke. Peak power was 43% lower in the older group compared to the younger (p?0.001) and was accompanied by a significantly lower RMS (p?0.05). No differences were observed in the other electromyography (EMG) parameters between the groups (p?>?0.05). ΔRMS from the first to the sixth second during each trial was found to increase significantly with the development of power output in both groups (p?0.05). For the first time during an all-out 6-s cycle trial, it has been demonstrated that older women's lower mechanical power output was accompanied by a significantly lower RMS, which indicates a decline in either the number of active of motor units or a reduced discharge rate. Hence, changes in motor units can be regarded as a contributory factor to the decline of muscle power with advancing age. Overall, though, similar neural strategies are adopted in both younger and older populations. 相似文献
85.
OBJECTIVE: The goal of this study was to examine the association between sexual abuse (SA) and initiation, cessation, and current cigarette smoking among a large representative adult population in France. METHOD: A random sample size of 12,256 adults (18-75 years of age) was interviewed by telephone concerning demographic variables, health practices and beliefs, and health status--for which SA and tobacco questions were included. Bivariate and multivariate analyses were conducted. RESULTS: Nearly 46% of SA survivors were current smokers compared to 34% of non-abused persons (p<.001). Survivors of SA consumed more cigarettes per day than non-abused individuals (14.5 vs. 12.4, p<.01). Survival analysis showed an increased risk of smoking initiation for respondents abused before 18 (adjusted relative hazard=1.55; p<.0001) with referent to the non-abused group. SA was not found to be a significant predictor of current smoking status among those who began smoking after the first incident of SA. Respondents who were not sexually abused were 1.8 times (95% CI, 1.12-2.99) more likely to quit smoking than people who began smoking after they were sexually abused. CONCLUSIONS: The early identification and treatment of sexually abused persons is critical to decrease smoking among adolescents and adults because of the association of SA with both smoking initiation and decreased cessation rates. It may be more difficult to detect an association between SA and current smoking due to the high rates of smoking and lower rates of quitting among the general French population. 相似文献
86.
Interest in consolidating service points within health sciences libraries continues. This article proposes a definition of a library single service point and mentions some notable examples in academic health sciences libraries. The experiences of two of these libraries are summarized and compared, and the advice culled from those experiences is shared. The advice is in the form of sharing lessons learned, answering six frequently asked questions about combining services and staff under a single service umbrella. The article offers insights for other library staff considering this type of service reorganization. 相似文献
87.
保罗&#;克里科摩尔 《航空档案》2008,(10)
在英国的行动
在“超级皇冠”项目初期,具备任务出动能力的SR-71的数量不断减少。2个飞行中队在1971年4月合并为1个。随着美国从南越撤军以及“赎罪日战争”最终结束,美军的部队授权飞机数量也在逐渐减少。到1977年,SR-71A的“主要授权飞机”(PAA)也减至6架,经费也相应削减。由于SR-71主要是一种成象平台, 相似文献
89.
90.