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   3660080篇
  免费   284763篇
  国内免费   6748篇
耳鼻咽喉   54537篇
儿科学   115774篇
妇产科学   102304篇
基础医学   521720篇
口腔科学   107112篇
临床医学   329327篇
内科学   702861篇
皮肤病学   75848篇
神经病学   301121篇
特种医学   144426篇
外国民族医学   1318篇
外科学   556255篇
综合类   88297篇
现状与发展   4篇
一般理论   1376篇
预防医学   292755篇
眼科学   87951篇
药学   275396篇
  5篇
中国医学   6861篇
肿瘤学   186343篇
  2018年   35886篇
  2016年   30677篇
  2015年   34974篇
  2014年   49977篇
  2013年   76862篇
  2012年   103671篇
  2011年   109993篇
  2010年   64771篇
  2009年   61541篇
  2008年   104538篇
  2007年   112591篇
  2006年   113338篇
  2005年   110949篇
  2004年   107290篇
  2003年   103430篇
  2002年   101952篇
  2001年   160098篇
  2000年   165429篇
  1999年   140430篇
  1998年   42047篇
  1997年   37813篇
  1996年   37417篇
  1995年   36007篇
  1994年   33855篇
  1993年   31529篇
  1992年   114390篇
  1991年   111527篇
  1990年   108640篇
  1989年   105120篇
  1988年   97708篇
  1987年   96361篇
  1986年   91543篇
  1985年   88069篇
  1984年   67054篇
  1983年   57629篇
  1982年   35386篇
  1981年   31607篇
  1979年   64411篇
  1978年   45814篇
  1977年   38754篇
  1976年   36592篇
  1975年   39230篇
  1974年   47923篇
  1973年   45975篇
  1972年   43419篇
  1971年   40264篇
  1970年   37937篇
  1969年   35946篇
  1968年   33258篇
  1967年   29782篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
31.
Adjuvant irradiation is the standard treatment after breast conservative surgery. Normofractionated regimen with an overall treatment time of 5 to 6 weeks is often considered as a limiting factor for irradiation compliance. In order to answer this issue, moderate and more recently extreme hypofractionated protocols appeared. We report here oncological outcomes and toxicity of hypofractionated breast irradiation. After defining the frame of moderate and extreme hypofractionated breast irradiations based on overall treatment time, patient selection criteria were listed. According to their levels of proof, the results of moderate and extreme hypofractionated breast irradiation were analysed. Overall treatment time for moderate hypofractionated breast irradiation ranged from 3 to 4 weeks, while for extreme hypofractionated breast irradiation, it was less than 1 week. For moderate hypofractionated breast irradiation, whole breast irradiation was currently performed with or without lymph node irradiation. Moderate hypofractionated breast irradiation has proven to be as safe and as efficient as normofractionated breast irradiation with level IA evidence. For extreme hypofractionated breast irradiation, phase III randomized trials confirmed that accelerated partial breast irradiation was non-inferior in terms of local control compared to normofractionated whole breast irradiation (with external beam radiation therapy and multicatheter brachytherapy), with similar acute and late toxicity. While the use of intraoperative breast irradiation remains under debate, new very accelerated partial breast irradiation (overall treatment time not exceeding 2 days) protocols emerged with encouraging results. Accelerated partial breast irradiation is warranted for extreme hypofractionated breast irradiation and is indicated for low-risk breast cancers. Moderate and extreme hypofractionated breast irradiation regimens are validated and can be routinely proposed according to patient selection criteria.  相似文献   
32.
33.
34.
Secondary tricuspid regurgitation (TR) caused by right ventricular enlargement in the setting of left heart disease/pulmonary hypertension has been well described. In contrast, that associated with right atrial enlargement—atrial functional TR (AF‐TR)—remains largely underappreciated. AF‐TR most often occurs in the setting of lone atrial fibrillation, although it is also seen in its absence (idiopathic AF‐TR). Several recent studies have found that the prevalence, hemodynamic significance, and prognosis of AF‐TR are not inconsequential, suggesting increased physician awareness of this novel clinical entity is warranted. This article discusses the pathogenesis, echocardiographic findings, and treatment of this underappreciated cause of secondary TR.  相似文献   
35.
36.
37.
38.
39.
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   
40.
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