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   230120篇
  免费   17517篇
  国内免费   763篇
耳鼻咽喉   2477篇
儿科学   6183篇
妇产科学   4820篇
基础医学   30093篇
口腔科学   5048篇
临床医学   22324篇
内科学   48163篇
皮肤病学   3072篇
神经病学   21768篇
特种医学   7638篇
外国民族医学   16篇
外科学   35566篇
综合类   3810篇
现状与发展   2篇
一般理论   312篇
预防医学   21538篇
眼科学   4698篇
药学   16036篇
  1篇
中国医学   466篇
肿瘤学   14369篇
  2023年   913篇
  2022年   1516篇
  2021年   3640篇
  2020年   2261篇
  2019年   3619篇
  2018年   4297篇
  2017年   3410篇
  2016年   3636篇
  2015年   4344篇
  2014年   6474篇
  2013年   9373篇
  2012年   13930篇
  2011年   15152篇
  2010年   8563篇
  2009年   7755篇
  2008年   14350篇
  2007年   15240篇
  2006年   14803篇
  2005年   15230篇
  2004年   14610篇
  2003年   13670篇
  2002年   13209篇
  2001年   2669篇
  2000年   2268篇
  1999年   2759篇
  1998年   3111篇
  1997年   2666篇
  1996年   2474篇
  1995年   2200篇
  1994年   1975篇
  1993年   1852篇
  1992年   1780篇
  1991年   1636篇
  1990年   1543篇
  1989年   1388篇
  1988年   1426篇
  1987年   1443篇
  1986年   1413篇
  1985年   1458篇
  1984年   1776篇
  1983年   1700篇
  1982年   2001篇
  1981年   1810篇
  1980年   1715篇
  1979年   1088篇
  1978年   1166篇
  1977年   1104篇
  1976年   986篇
  1975年   844篇
  1974年   860篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
2.
3.
4.
5.
6.
7.
8.

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   
9.

Objective

To determine whether differences in combination DTaP vaccine types at 2, 4 and 6?months of age were associated with mortality (all-cause or non-specific), within 30?days of vaccination.

Design

Observational nationwide cohort study.

Setting

Linked population data from the Australian Childhood Immunisation Register and National Death Index.

Participants

Australian infants administered a combination trivalent, quadrivalent or hexavalent DTaP vaccine (DTaP types) between January 1999 and December 2010 at 2, 4 and 6?months as part of the primary vaccination series. The study population included 2.9, 2.6, & 2.3?million children in the 2, 4 and 6?month vaccine cohorts, respectively.

Main outcome measures

Infants were evaluated for the primary outcome of all-cause mortality within 30?days. A secondary outcome was non-specific mortality (unknown cause of death) within 30?days of vaccination. Non-specific mortality was defined as underlying or other cause of death codes, R95 ‘Sudden infant death syndrome’, R96 ‘Other sudden death, cause unknown’, R98 ‘Unattended death’, R99 ‘Other ill-defined and unspecified cause of mortality’ or where no cause of death was recorded.

Results

The rate of 30?day all-cause mortality was low and declined from 127.4 to 59.3 deaths per 100,000 person-years between 2 and 6?month cohorts. When compared with trivalent DTaP vaccines, no elevated risk in all-cause or non-specific mortality was seen with any quadrivalent or hexavalent DTaP vaccines, for any cohort.

Conclusion

Use of routine DTaP combination vaccines with differing disease antigens administered during the first six months of life is not associated with infant mortality.  相似文献   
10.
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