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   3349365篇
  免费   234964篇
  国内免费   8676篇
耳鼻咽喉   46123篇
儿科学   110315篇
妇产科学   92551篇
基础医学   472159篇
口腔科学   92975篇
临床医学   302157篇
内科学   653819篇
皮肤病学   80645篇
神经病学   271679篇
特种医学   127949篇
外国民族医学   919篇
外科学   496937篇
综合类   65965篇
现状与发展   6篇
一般理论   1190篇
预防医学   258219篇
眼科学   76390篇
药学   250608篇
  13篇
中国医学   7439篇
肿瘤学   184947篇
  2021年   26485篇
  2019年   27434篇
  2018年   39362篇
  2017年   29952篇
  2016年   34233篇
  2015年   38367篇
  2014年   52056篇
  2013年   77868篇
  2012年   105484篇
  2011年   111581篇
  2010年   66370篇
  2009年   62570篇
  2008年   103045篇
  2007年   109588篇
  2006年   111161篇
  2005年   106498篇
  2004年   102130篇
  2003年   98310篇
  2002年   94793篇
  2001年   161066篇
  2000年   165305篇
  1999年   139055篇
  1998年   39210篇
  1997年   34687篇
  1996年   34902篇
  1995年   33690篇
  1994年   30680篇
  1993年   28768篇
  1992年   107346篇
  1991年   103306篇
  1990年   100476篇
  1989年   97113篇
  1988年   88793篇
  1987年   86704篇
  1986年   81633篇
  1985年   77673篇
  1984年   57653篇
  1983年   48581篇
  1982年   28564篇
  1979年   51230篇
  1978年   35726篇
  1977年   31073篇
  1976年   28210篇
  1975年   30618篇
  1974年   36059篇
  1973年   34494篇
  1972年   32556篇
  1971年   30278篇
  1970年   27877篇
  1969年   26917篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
62.
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   
63.
64.
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   

65.
66.
67.
68.
69.
70.
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