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   3200363篇
  免费   234365篇
  国内免费   8632篇
耳鼻咽喉   43182篇
儿科学   107100篇
妇产科学   88579篇
基础医学   453277篇
口腔科学   89133篇
临床医学   292673篇
内科学   626340篇
皮肤病学   75521篇
神经病学   261756篇
特种医学   123205篇
外国民族医学   1009篇
外科学   477711篇
综合类   67363篇
现状与发展   5篇
一般理论   1263篇
预防医学   247810篇
眼科学   72151篇
药学   233843篇
  11篇
中国医学   6560篇
肿瘤学   174868篇
  2019年   24971篇
  2018年   35377篇
  2017年   27210篇
  2016年   31306篇
  2015年   35285篇
  2014年   48557篇
  2013年   73667篇
  2012年   97573篇
  2011年   103330篇
  2010年   62166篇
  2009年   59340篇
  2008年   96638篇
  2007年   102487篇
  2006年   104454篇
  2005年   100082篇
  2004年   96803篇
  2003年   93480篇
  2002年   90120篇
  2001年   152872篇
  2000年   156664篇
  1999年   132154篇
  1998年   37991篇
  1997年   33878篇
  1996年   33952篇
  1995年   32893篇
  1994年   30316篇
  1993年   28258篇
  1992年   103547篇
  1991年   100033篇
  1990年   97244篇
  1989年   93912篇
  1988年   85849篇
  1987年   84658篇
  1986年   79264篇
  1985年   75922篇
  1984年   56614篇
  1983年   47979篇
  1982年   28541篇
  1981年   25567篇
  1979年   50446篇
  1978年   35862篇
  1977年   30396篇
  1976年   28340篇
  1975年   30065篇
  1974年   35805篇
  1973年   34118篇
  1972年   31760篇
  1971年   29569篇
  1970年   27245篇
  1969年   25988篇
排序方式: 共有10000条查询结果,搜索用时 62 毫秒
51.
52.
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   
53.
54.
Introduction: In men, lower urinary tract symptoms (LUTS) are primarily attributed to benign prostatic hyperplasia (BPH). Therapeutic options are targeted to relax prostate smooth muscle and/or reduce prostate enlargement.

Areas covered: This article reviews the major preclinical and clinical data on PDE5 inhibitors with a specific focus on tadalafil. It includes details of the role of the nitric oxide (NO)-cyclic guanosine monophosphate (cGMP) – PDE5 pathway in the LUT organs (bladder and prostate) in addition to the available data on tadalafil in patients with LUTS secondary to BPH with or without erectile dysfunction (ED).

Expert opinion: Preclinical and clinical data have clearly demonstrated that PDE5 inhibitors induce bladder and prostate relaxation, which contributes to the improvement seen in storage symptoms in both animal models of bladder and prostate hypercontractility. Tadalafil is effective both as a monotherapy and add-on therapy in patients with LUTS secondary to BPH. Furthermore, as LUTS-BPH and ED are urological disorders that commonly coexist in aging men, tadalafil is more advantageous than α1-adrenoceptors and should be used as the first option. Tadalafil is a safe and tolerable therapy and unlike α1- adrenoceptors and 5-alpha reductase inhibitors, which can cause sexual dysfunctions, tadalafil improves sexual function.  相似文献   

55.
56.
57.
58.
59.
60.
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