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   3274475篇
  免费   236032篇
  国内免费   9107篇
耳鼻咽喉   45518篇
儿科学   106601篇
妇产科学   92094篇
基础医学   460975篇
口腔科学   92185篇
临床医学   295048篇
内科学   637609篇
皮肤病学   76554篇
神经病学   265484篇
特种医学   129189篇
外国民族医学   961篇
外科学   494787篇
综合类   69794篇
现状与发展   7篇
一般理论   1161篇
预防医学   254078篇
眼科学   74521篇
药学   240044篇
  10篇
中国医学   6474篇
肿瘤学   176520篇
  2018年   36448篇
  2017年   29061篇
  2016年   32473篇
  2015年   37791篇
  2014年   50297篇
  2013年   73608篇
  2012年   101331篇
  2011年   102750篇
  2010年   61391篇
  2009年   59984篇
  2008年   94462篇
  2007年   101196篇
  2006年   102881篇
  2005年   105599篇
  2004年   103738篇
  2003年   97068篇
  2002年   89797篇
  2001年   149106篇
  2000年   151336篇
  1999年   129782篇
  1998年   37405篇
  1997年   33292篇
  1996年   33317篇
  1995年   32200篇
  1994年   29716篇
  1993年   27860篇
  1992年   103974篇
  1991年   100792篇
  1990年   98173篇
  1989年   94934篇
  1988年   87381篇
  1987年   85873篇
  1986年   80766篇
  1985年   77032篇
  1984年   57704篇
  1983年   49090篇
  1982年   29118篇
  1981年   26142篇
  1979年   52980篇
  1978年   37591篇
  1977年   31747篇
  1976年   29307篇
  1975年   31960篇
  1974年   38365篇
  1973年   36464篇
  1972年   34483篇
  1971年   32132篇
  1970年   29916篇
  1969年   28847篇
  1968年   26478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