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   2583570篇
  免费   189305篇
  国内免费   7558篇
耳鼻咽喉   34272篇
儿科学   85212篇
妇产科学   71574篇
基础医学   363645篇
口腔科学   69683篇
临床医学   234562篇
内科学   515557篇
皮肤病学   62451篇
神经病学   213476篇
特种医学   99894篇
外国民族医学   736篇
外科学   386495篇
综合类   50394篇
现状与发展   5篇
一般理论   968篇
预防医学   196220篇
眼科学   56669篇
药学   188026篇
  8篇
中国医学   5331篇
肿瘤学   145255篇
  2021年   19990篇
  2019年   20628篇
  2018年   29299篇
  2017年   22598篇
  2016年   26232篇
  2015年   29507篇
  2014年   40443篇
  2013年   60442篇
  2012年   80231篇
  2011年   84501篇
  2010年   51024篇
  2009年   49164篇
  2008年   79050篇
  2007年   83846篇
  2006年   85585篇
  2005年   81743篇
  2004年   78731篇
  2003年   76067篇
  2002年   73343篇
  2001年   128416篇
  2000年   131338篇
  1999年   110511篇
  1998年   31259篇
  1997年   27922篇
  1996年   28220篇
  1995年   27385篇
  1994年   25068篇
  1993年   23422篇
  1992年   85168篇
  1991年   81576篇
  1990年   78796篇
  1989年   76074篇
  1988年   69483篇
  1987年   68008篇
  1986年   63551篇
  1985年   60524篇
  1984年   44946篇
  1983年   37948篇
  1982年   22460篇
  1981年   19987篇
  1979年   38969篇
  1978年   27442篇
  1977年   23258篇
  1976年   21499篇
  1975年   22817篇
  1974年   26792篇
  1973年   25374篇
  1972年   23755篇
  1971年   21956篇
  1970年   20185篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
42.
43.
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   
44.
45.
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   

46.
47.
48.
49.
50.
Pharmaceutical Chemistry Journal - An HPLC-MS method for simultaneous quantitative determination of a novel gestagenic pharmaceutical and two of its metabolites in rat and rabbit blood sera was...  相似文献   
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