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   4969418篇
  免费   386997篇
  国内免费   17552篇
耳鼻咽喉   69120篇
儿科学   159946篇
妇产科学   132641篇
基础医学   746230篇
口腔科学   137756篇
临床医学   462790篇
内科学   904295篇
皮肤病学   118065篇
神经病学   416706篇
特种医学   191845篇
外国民族医学   1064篇
外科学   738500篇
综合类   139838篇
现状与发展   24篇
一般理论   2842篇
预防医学   418864篇
眼科学   116752篇
药学   353715篇
  30篇
中国医学   13826篇
肿瘤学   249118篇
  2021年   57194篇
  2019年   59588篇
  2018年   76745篇
  2017年   58913篇
  2016年   65220篇
  2015年   77648篇
  2014年   112106篇
  2013年   178309篇
  2012年   145372篇
  2011年   153865篇
  2010年   132954篇
  2009年   132143篇
  2008年   138587篇
  2007年   148345篇
  2006年   155769篇
  2005年   149475篇
  2004年   149782篇
  2003年   139386篇
  2002年   128261篇
  2001年   194487篇
  2000年   191249篇
  1999年   172325篇
  1998年   75487篇
  1997年   70359篇
  1996年   68272篇
  1995年   63777篇
  1994年   57752篇
  1993年   53493篇
  1992年   126760篇
  1991年   121725篇
  1990年   117372篇
  1989年   113857篇
  1988年   104936篇
  1987年   102897篇
  1986年   97410篇
  1985年   94684篇
  1984年   76885篇
  1983年   67950篇
  1982年   51285篇
  1981年   47454篇
  1980年   44454篇
  1979年   67014篇
  1978年   52592篇
  1977年   46116篇
  1976年   43145篇
  1975年   43666篇
  1974年   48738篇
  1973年   46692篇
  1972年   43796篇
  1971年   40705篇
排序方式: 共有10000条查询结果,搜索用时 16 毫秒
121.
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   
122.
123.
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   

124.
125.
126.
127.
Graefe's Archive for Clinical and Experimental Ophthalmology - The published online version contains mistake as the author's first name and last name have been interchanged as "Hild...  相似文献   
128.
129.
130.
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