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   3254659篇
  免费   231213篇
  国内免费   8428篇
耳鼻咽喉   44828篇
儿科学   108000篇
妇产科学   90314篇
基础医学   458529篇
口腔科学   89602篇
临床医学   296399篇
内科学   633804篇
皮肤病学   78045篇
神经病学   263757篇
特种医学   125686篇
外国民族医学   918篇
外科学   486116篇
综合类   65457篇
现状与发展   6篇
一般理论   1184篇
预防医学   246204篇
眼科学   73787篇
药学   243507篇
  13篇
中国医学   7093篇
肿瘤学   181051篇
  2019年   25522篇
  2018年   36054篇
  2017年   27907篇
  2016年   32249篇
  2015年   36188篇
  2014年   49674篇
  2013年   74296篇
  2012年   99136篇
  2011年   104797篇
  2010年   63045篇
  2009年   60230篇
  2008年   97672篇
  2007年   103917篇
  2006年   105773篇
  2005年   101405篇
  2004年   97433篇
  2003年   93973篇
  2002年   90743篇
  2001年   159371篇
  2000年   163427篇
  1999年   137533篇
  1998年   38884篇
  1997年   34513篇
  1996年   34696篇
  1995年   33521篇
  1994年   30549篇
  1993年   28652篇
  1992年   106397篇
  1991年   102440篇
  1990年   99598篇
  1989年   96371篇
  1988年   88035篇
  1987年   86022篇
  1986年   80907篇
  1985年   76986篇
  1984年   57133篇
  1983年   48154篇
  1982年   28302篇
  1981年   25092篇
  1979年   50571篇
  1978年   35274篇
  1977年   30603篇
  1976年   27791篇
  1975年   30136篇
  1974年   35373篇
  1973年   33757篇
  1972年   31872篇
  1971年   29635篇
  1970年   27254篇
  1969年   26244篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
52.
53.
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   
54.
55.
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   

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