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   3510838篇
  免费   250263篇
  国内免费   9569篇
耳鼻咽喉   49707篇
儿科学   113790篇
妇产科学   99624篇
基础医学   494104篇
口腔科学   100783篇
临床医学   312903篇
内科学   685603篇
皮肤病学   84283篇
神经病学   287235篇
特种医学   134877篇
外国民族医学   1123篇
外科学   526433篇
综合类   73118篇
现状与发展   11篇
一般理论   1316篇
预防医学   268431篇
眼科学   81524篇
药学   259781篇
  10篇
中国医学   7424篇
肿瘤学   188590篇
  2018年   39333篇
  2017年   30054篇
  2016年   34182篇
  2015年   38464篇
  2014年   52591篇
  2013年   79298篇
  2012年   106293篇
  2011年   112686篇
  2010年   67211篇
  2009年   63585篇
  2008年   104857篇
  2007年   112171篇
  2006年   113382篇
  2005年   109014篇
  2004年   105085篇
  2003年   101530篇
  2002年   98131篇
  2001年   162635篇
  2000年   166914篇
  1999年   141110篇
  1998年   40515篇
  1997年   35887篇
  1996年   33364篇
  1995年   34185篇
  1994年   31521篇
  1993年   29554篇
  1992年   109960篇
  1991年   106217篇
  1990年   103249篇
  1989年   100008篇
  1988年   92285篇
  1987年   90552篇
  1986年   85609篇
  1985年   81805篇
  1984年   61292篇
  1983年   51961篇
  1982年   31083篇
  1981年   27824篇
  1979年   55866篇
  1978年   39648篇
  1977年   34203篇
  1976年   31363篇
  1975年   34451篇
  1974年   40754篇
  1973年   39221篇
  1972年   37081篇
  1971年   34606篇
  1970年   32273篇
  1969年   31213篇
  1968年   29030篇
排序方式: 共有10000条查询结果,搜索用时 203 毫秒
61.
62.
63.
64.
65.
66.
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   
67.
68.
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   

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