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   2592726篇
  免费   189783篇
  国内免费   7604篇
耳鼻咽喉   34399篇
儿科学   85437篇
妇产科学   71759篇
基础医学   364819篇
口腔科学   69963篇
临床医学   235345篇
内科学   517610篇
皮肤病学   62711篇
神经病学   214482篇
特种医学   100221篇
外国民族医学   739篇
外科学   387763篇
综合类   50477篇
现状与发展   5篇
一般理论   972篇
预防医学   196718篇
眼科学   56813篇
药学   188583篇
  8篇
中国医学   5353篇
肿瘤学   145936篇
  2021年   20278篇
  2019年   20848篇
  2018年   29510篇
  2017年   22761篇
  2016年   26414篇
  2015年   29724篇
  2014年   40779篇
  2013年   60841篇
  2012年   80904篇
  2011年   85161篇
  2010年   51392篇
  2009年   49457篇
  2008年   79588篇
  2007年   84374篇
  2006年   86087篇
  2005年   82247篇
  2004年   79217篇
  2003年   76476篇
  2002年   73721篇
  2001年   128582篇
  2000年   131519篇
  1999年   110637篇
  1998年   31328篇
  1997年   27978篇
  1996年   28284篇
  1995年   27436篇
  1994年   25131篇
  1993年   23460篇
  1992年   85286篇
  1991年   81654篇
  1990年   78883篇
  1989年   76139篇
  1988年   69546篇
  1987年   68066篇
  1986年   63629篇
  1985年   60589篇
  1984年   44991篇
  1983年   37989篇
  1982年   22491篇
  1981年   20019篇
  1979年   39012篇
  1978年   27462篇
  1977年   23282篇
  1976年   21516篇
  1975年   22835篇
  1974年   26816篇
  1973年   25395篇
  1972年   23790篇
  1971年   21982篇
  1970年   20206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