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   2589741篇
  免费   189591篇
  国内免费   7572篇
耳鼻咽喉   34433篇
儿科学   85429篇
妇产科学   71655篇
基础医学   364618篇
口腔科学   69902篇
临床医学   235172篇
内科学   516599篇
皮肤病学   62616篇
神经病学   213964篇
特种医学   100175篇
外国民族医学   736篇
外科学   387331篇
综合类   50450篇
现状与发展   5篇
一般理论   977篇
预防医学   196569篇
眼科学   56934篇
药学   188442篇
  8篇
中国医学   5348篇
肿瘤学   145541篇
  2021年   20067篇
  2019年   20718篇
  2018年   29384篇
  2017年   22692篇
  2016年   26343篇
  2015年   29628篇
  2014年   40577篇
  2013年   60651篇
  2012年   80501篇
  2011年   84800篇
  2010年   51176篇
  2009年   49289篇
  2008年   79300篇
  2007年   84137篇
  2006年   85867篇
  2005年   82039篇
  2004年   79033篇
  2003年   76328篇
  2002年   73553篇
  2001年   128617篇
  2000年   131523篇
  1999年   110655篇
  1998年   31338篇
  1997年   27983篇
  1996年   28288篇
  1995年   27440篇
  1994年   25124篇
  1993年   23456篇
  1992年   85254篇
  1991年   81646篇
  1990年   78876篇
  1989年   76141篇
  1988年   69539篇
  1987年   68071篇
  1986年   63611篇
  1985年   60574篇
  1984年   44995篇
  1983年   38000篇
  1982年   22491篇
  1981年   20019篇
  1979年   39014篇
  1978年   27496篇
  1977年   23304篇
  1976年   21530篇
  1975年   22859篇
  1974年   26827篇
  1973年   25412篇
  1972年   23809篇
  1971年   21992篇
  1970年   20214篇
排序方式: 共有10000条查询结果,搜索用时 31 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