收费全文 | 2345424篇 |
免费 | 184362篇 |
国内免费 | 7731篇 |
耳鼻咽喉 | 31879篇 |
儿科学 | 77391篇 |
妇产科学 | 66424篇 |
基础医学 | 331731篇 |
口腔科学 | 65878篇 |
临床医学 | 207029篇 |
内科学 | 468571篇 |
皮肤病学 | 53465篇 |
神经病学 | 188924篇 |
特种医学 | 94311篇 |
外国民族医学 | 617篇 |
外科学 | 364916篇 |
综合类 | 52498篇 |
现状与发展 | 3篇 |
一般理论 | 683篇 |
预防医学 | 182764篇 |
眼科学 | 52420篇 |
药学 | 171540篇 |
6篇 | |
中国医学 | 4257篇 |
肿瘤学 | 122210篇 |
2018年 | 22794篇 |
2016年 | 20729篇 |
2015年 | 23424篇 |
2014年 | 32636篇 |
2013年 | 49349篇 |
2012年 | 63374篇 |
2011年 | 67925篇 |
2010年 | 41612篇 |
2009年 | 40049篇 |
2008年 | 64492篇 |
2007年 | 69461篇 |
2006年 | 70882篇 |
2005年 | 69071篇 |
2004年 | 66275篇 |
2003年 | 64493篇 |
2002年 | 62281篇 |
2001年 | 108034篇 |
2000年 | 111227篇 |
1999年 | 93719篇 |
1998年 | 27843篇 |
1997年 | 24995篇 |
1996年 | 25842篇 |
1995年 | 25335篇 |
1994年 | 23895篇 |
1993年 | 22253篇 |
1992年 | 77398篇 |
1991年 | 75839篇 |
1990年 | 73857篇 |
1989年 | 70816篇 |
1988年 | 66023篇 |
1987年 | 64725篇 |
1986年 | 61568篇 |
1985年 | 59066篇 |
1984年 | 44716篇 |
1983年 | 38235篇 |
1982年 | 23570篇 |
1981年 | 21056篇 |
1980年 | 19749篇 |
1979年 | 41443篇 |
1978年 | 29674篇 |
1977年 | 25291篇 |
1976年 | 23550篇 |
1975年 | 25318篇 |
1974年 | 29824篇 |
1973年 | 28607篇 |
1972年 | 26814篇 |
1971年 | 24846篇 |
1970年 | 22904篇 |
1969年 | 21848篇 |
1968年 | 20526篇 |
Objectives
To investigate whether functional overreaching affects locomotor system behaviour when running at fixed relative intensities and if any effects were associated with changes in running performance.Design
Prospective intervention study.Methods
Ten trained male runners completed three training blocks in a fixed order. Training consisted of one week of light training (baseline), two weeks of heavy training designed to induce functional overreaching, and ten days of light taper training designed to allow athletes to recover from, and adapt to, the heavy training. Locomotor behaviour, 5-km time trial performance, and subjective reports of training status (Daily Analysis of Life Demands for Athletes (DALDA) questionnaire) were assessed at the completion of each training block. Locomotor behaviour was assessed using detrended fluctuation analysis of stride intervals during running at speeds corresponding to 65% and 85% of maximum heart rate (HRmax) at baseline.Results
Time trial performance (effect size ±95% confidence interval (ES): 0.16 ± 0.06; p < 0.001), locomotor behaviour at 65% HRmax (ES: ?1.12 ± 0.95; p = 0.026), and DALDA (ES: 2.55 ± 0.80; p < 0.001) were all detrimentally affected by the heavy training. Time trial performance improved relative to baseline after the taper (ES: ?0.16 ± 0.10; p = 0.003) but locomotor behaviour at 65% HRmax (ES: ?1.18 ± 1.17; p = 0.048) and DALDA (ES: 0.92 ± 0.90; p = 0.045) remained impaired.Conclusions
Locomotor behaviour during running at 65% HRmax was impaired by functional overreaching and remained impaired after a 10-day taper, despite improved running performance. Locomotor changes may increase injury risk and should be considered within athlete monitoring programs independently of performance changes. 相似文献Introduction/Hypothesis
Recruitment of participants into phase 1 vaccine clinical trials can be challenging since these vaccines have not been used in humans and there is no perceived benefit to the participant. Occasionally, as was the case with a phase 1 clinical trial of an Ebola vaccine in Halifax, Canada, during the 2014–2016 West African Ebola virus outbreak, recruitment is less difficult. In this study, we explored the motivations of participants in two phase 1 vaccine trials that were concurrently enrolling at the same centre and compared the motivations of participants in a high-profile phase 1 Ebola vaccine trial to those in a less high-profile phase 1 adjuvanted seasonal influenza vaccine study.Methods
An online survey which included participants’ prior experience with clinical trials, motivations to participate (including financial incentives), and demographic information was developed to examine the motivations of healthy participants in two phase 1 clinical vaccine trials conducted at the Canadian Center for Vaccinology in Halifax, Nova Scotia. Participants were invited via email to complete the online survey. Readability and clarity were assessed through pilot testing.Results
A total of 49 (55.7%) of 88 participants of the two studies completed the survey (22 [55%] of 40 participants from the Ebola vaccine study and 27 [56.3%] of 48 from the adjuvanted influenza vaccine study). Motivations that were most frequently ranked among participants' top three in both trials were (1) wanting to contribute to the health of others, (2) wanting to participate in something important, (3) wanting to contribute to the advancement of science, and (4) wanting to receive an incentive such as money or a tablet.Conclusions/Recommendations
Although media attention and financial compensation were more often cited by Ebola vaccine trial participants as a reason to participate, both altruistic and self-interested factors were important motivations for participants in their decision to participate in a phase 1 vaccine clinical trial. 相似文献Methods: The purpose of this study was to examine the degree to which several personal factors and school characteristics affect and explain students’ self-determination. A total of 232 students with intellectual disability from Spain participated. Their self-determination level was assessed by the ARC-INICO Scale.
Results: Students with moderate levels of intellectual disability obtained significantly lower scores on self-determination than their peers with mild intellectual disability. There were significant differences in relation to the level of support needs and their experience with transition programs. The level of support needs was a significant predictor.
Conclusion: These findings contribute to current research in this field and practical implications were discussed. 相似文献