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   2585617篇
  免费   189397篇
  国内免费   7565篇
耳鼻咽喉   34292篇
儿科学   85346篇
妇产科学   71671篇
基础医学   363903篇
口腔科学   69739篇
临床医学   234698篇
内科学   516019篇
皮肤病学   62468篇
神经病学   213635篇
特种医学   99942篇
外国民族医学   737篇
外科学   386807篇
综合类   50412篇
现状与发展   5篇
一般理论   969篇
预防医学   196312篇
眼科学   56723篇
药学   188178篇
  8篇
中国医学   5339篇
肿瘤学   145376篇
  2021年   20030篇
  2019年   20661篇
  2018年   29323篇
  2017年   22623篇
  2016年   26265篇
  2015年   29552篇
  2014年   40504篇
  2013年   60508篇
  2012年   80353篇
  2011年   84636篇
  2010年   51082篇
  2009年   49210篇
  2008年   79148篇
  2007年   83980篇
  2006年   85691篇
  2005年   81864篇
  2004年   78856篇
  2003年   76163篇
  2002年   73436篇
  2001年   128478篇
  2000年   131383篇
  1999年   110548篇
  1998年   31284篇
  1997年   27950篇
  1996年   28244篇
  1995年   27408篇
  1994年   25087篇
  1993年   23437篇
  1992年   85209篇
  1991年   81597篇
  1990年   78817篇
  1989年   76091篇
  1988年   69491篇
  1987年   68016篇
  1986年   63568篇
  1985年   60530篇
  1984年   44967篇
  1983年   37963篇
  1982年   22466篇
  1981年   19996篇
  1979年   38976篇
  1978年   27465篇
  1977年   23266篇
  1976年   21508篇
  1975年   22822篇
  1974年   26792篇
  1973年   25380篇
  1972年   23769篇
  1971年   21969篇
  1970年   20193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