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   1356439篇
  免费   100709篇
  国内免费   2227篇
耳鼻咽喉   19138篇
儿科学   44510篇
妇产科学   39189篇
基础医学   198262篇
口腔科学   36332篇
临床医学   117076篇
内科学   268248篇
皮肤病学   27438篇
神经病学   106918篇
特种医学   53092篇
外国民族医学   369篇
外科学   210030篇
综合类   27546篇
现状与发展   1篇
一般理论   396篇
预防医学   99476篇
眼科学   30953篇
药学   103474篇
  1篇
中国医学   2580篇
肿瘤学   74346篇
  2018年   14235篇
  2017年   10665篇
  2016年   11909篇
  2015年   13748篇
  2014年   19087篇
  2013年   28372篇
  2012年   39766篇
  2011年   42411篇
  2010年   24786篇
  2009年   23185篇
  2008年   40218篇
  2007年   43361篇
  2006年   43497篇
  2005年   42770篇
  2004年   40971篇
  2003年   39646篇
  2002年   38724篇
  2001年   59017篇
  2000年   60353篇
  1999年   51547篇
  1998年   15075篇
  1997年   13461篇
  1996年   13590篇
  1995年   12853篇
  1994年   12229篇
  1993年   11337篇
  1992年   41525篇
  1991年   40826篇
  1990年   40341篇
  1989年   39102篇
  1988年   36541篇
  1987年   35732篇
  1986年   34070篇
  1985年   32491篇
  1984年   24267篇
  1983年   21100篇
  1982年   12665篇
  1981年   11212篇
  1979年   22868篇
  1978年   16107篇
  1977年   13915篇
  1976年   13136篇
  1975年   14361篇
  1974年   16827篇
  1973年   16248篇
  1972年   15453篇
  1971年   14364篇
  1970年   13343篇
  1969年   12829篇
  1968年   12088篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
5.
6.
7.
Heart Failure Reviews - The nitric oxide (NO)–guanylate cyclase (GC)–cyclic guanosine monophosphate (cGMP) pathway plays an important role in cardiovascular, pulmonary and renal...  相似文献   
8.
Vaccination is a vital health care initiative to prevent individual and population infection. To increase vaccination rates the federal government implemented the ‘No Jab, No Pay’ policy, where eligibility for several government benefits required children to be fully vaccinated by removing ‘conscientious objections’ and expanding the age range of children whose families receive benefits. This study assesses the impact of this policy at a local area within a single medical practice community in NSW, Australia. A retrospective clinical audit was performed between 2012 and 2017 on a single general practice's vaccination records for children ≤19 years. Catch-up vaccinations were assessed based on age at vaccination. Incidence of catch-up vaccinations was assessed for each of four years before and two years after the implementation of the ‘No Jab, No Pay’ policy in January 2016, along with the age of children and vaccination(s) given. Catch-up vaccinations were assessed temporally either side of implementation of ‘No Jab, No Pay’. Comparing the average annual vaccination catch-up incidence rate of 6.2% pre-implementation (2012–2015), there was an increase to 9.2% in 2016 (p < .001) and 7.8% in 2017 (p = .027). Secondary outcome measurement of catch-up vaccination incidence rates before (2012–2015) and after (2016–2017) ‘No Jab, No Pay’ implementation showed statistically significant increases for children aged 8–11 years (3.2%–5.6%, p = .038), 12–15 years (7.5%–14.7%, p < .001) and 16–19 years (3.3%–10.2%, p < .001) along with a statistically significant reduction in children aged 1–3 years (11.4%–6.2%, p = .015). Also, catch-up rates for DTPa significantly increased after program implementation. This study demonstrates that the Australian federal government vaccination policy ‘No Jab, No Pay’ was coincident with an increase in catch-up vaccinations within a rural NSW community served by one medical practice, especially for older children.  相似文献   
9.
10.
G. Berlin  M. Hammar  L. Tapper 《Platelets》2019,30(4):473-479
Platelets are needed to prevent or arrest bleeding and aggregate at the site of injury upon vascular damage. Platelets express receptors for estrogens which might affect the function of the platelets and their hemostatic ability. The aim was to identify possible differences in platelet function related to age, gender, and phases of the menstrual cycle by use of impedance aggregometry with Multiplate. In the first part of the study, platelet function was assessed in 60 healthy individuals (30 men and 30 women) in each of three age groups (20–25, 40–45, and 60–65 years). In the second part of the study, the platelet function was analyzed on four occasions during the menstrual cycle in women without oral contraceptives (OCs) (n = 17) and compared to 19 women on OCs and 18 men of similar age (20–40 years). For the women on OCs, aggregation was analyzed once during the tablet-free week and once late during the period with OCs. The men were sampled once. Women of younger age (<45 years) had significantly higher agonist-induced aggregation response than both men and post-menopausal women (60–65 years). The agonist-induced aggregation response did not differ between phases of the menstrual cycle or OC use. The results suggest that estradiol and/or progesterone affect spontaneous aggregation since it was found to be lowest in the mid-luteal phase. Spontaneous aggregation was significantly lower in women on OCs than in both men and women without OCs. Our findings indicate that fertile age is associated with higher aggregation response capacity of the platelets, possibly to prevent excessive bleeding during menstruation, but this response capacity is not altered during the menstrual cycle or by use of OCs.  相似文献   
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