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   4106153篇
  免费   309999篇
  国内免费   10294篇
耳鼻咽喉   58091篇
儿科学   131238篇
妇产科学   111962篇
基础医学   573544篇
口腔科学   118877篇
临床医学   378393篇
内科学   798812篇
皮肤病学   92271篇
神经病学   341511篇
特种医学   159376篇
外国民族医学   1438篇
外科学   615793篇
综合类   91377篇
现状与发展   6篇
一般理论   1738篇
预防医学   328816篇
眼科学   95467篇
药学   303839篇
  11篇
中国医学   8119篇
肿瘤学   215767篇
  2018年   45097篇
  2017年   34417篇
  2016年   39032篇
  2015年   44386篇
  2014年   61982篇
  2013年   94059篇
  2012年   126003篇
  2011年   133406篇
  2010年   79614篇
  2009年   75711篇
  2008年   124752篇
  2007年   132517篇
  2006年   134350篇
  2005年   129751篇
  2004年   124894篇
  2003年   120170篇
  2002年   116906篇
  2001年   187419篇
  2000年   193018篇
  1999年   163584篇
  1998年   48582篇
  1997年   43338篇
  1996年   42996篇
  1995年   41694篇
  1994年   38700篇
  1993年   36208篇
  1992年   129818篇
  1991年   125585篇
  1990年   121372篇
  1989年   117286篇
  1988年   108391篇
  1987年   106776篇
  1986年   100850篇
  1985年   96628篇
  1984年   72698篇
  1983年   62066篇
  1982年   37404篇
  1981年   33660篇
  1979年   66771篇
  1978年   47259篇
  1977年   40044篇
  1976年   37511篇
  1975年   39611篇
  1974年   48007篇
  1973年   45827篇
  1972年   43110篇
  1971年   39928篇
  1970年   37316篇
  1969年   35285篇
  1968年   32453篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
61.
62.
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   
63.
64.
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   

65.
66.
67.
68.
Academic output is just one aspect of a successful career as a plastic surgeon. However, for those with a strong interest in academia, the academic output of a department will likely be a key factor when deciding how to rank jobs. The aim of this study was to quantify and rank the academic output of plastic surgery units across the UK and Ireland. The Institute for Scientific Information (ISI) Web of Science Bibliometric analysis tool was used to collate cumulative (1950–2016), 10 year (2006–2016) and 3 years (2013–2015) research output data for plastic surgery units in the UK and Ireland. Sixty-six plastic surgery units were identified. Departments were ranked for each time period according to the number of papers produced, number of citations (Nc) and h-index (a measure of the impact of scientific output). The top 3 departments for number of papers in the last 10 years were The Royal Free Hospital, London (226) Broomfield Hospital, Chelmsford (218), and Morriston Hospital and Swansea (188). The top 3 for h-number were The Royal Free Hospital (21) Wythenshawe Hospital, Manchester (18) and Morriston Hospital (17). Academic output varies across plastic surgery units in the UK and Ireland. A number of departments have consistently maintained high academic outputs across the years and will be of interest to surgeons hoping to pursue a career in academia.  相似文献   
69.
70.
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