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   180057篇
  免费   7675篇
  国内免费   413篇
耳鼻咽喉   2482篇
儿科学   5112篇
妇产科学   4104篇
基础医学   25853篇
口腔科学   7033篇
临床医学   10656篇
内科学   39558篇
皮肤病学   4883篇
神经病学   14431篇
特种医学   4492篇
外国民族医学   1篇
外科学   20756篇
综合类   813篇
一般理论   30篇
预防医学   21519篇
眼科学   4540篇
药学   13991篇
中国医学   809篇
肿瘤学   7082篇
  2023年   952篇
  2022年   1000篇
  2021年   3103篇
  2020年   1792篇
  2019年   3324篇
  2018年   5560篇
  2017年   3544篇
  2016年   3512篇
  2015年   4005篇
  2014年   4540篇
  2013年   6640篇
  2012年   11354篇
  2011年   12064篇
  2010年   5996篇
  2009年   4398篇
  2008年   9688篇
  2007年   10315篇
  2006年   9765篇
  2005年   9275篇
  2004年   8595篇
  2003年   8001篇
  2002年   7547篇
  2001年   5234篇
  2000年   5772篇
  1999年   4396篇
  1998年   783篇
  1992年   2351篇
  1991年   2120篇
  1990年   2053篇
  1989年   1781篇
  1988年   1679篇
  1987年   1579篇
  1986年   1604篇
  1985年   1507篇
  1984年   1073篇
  1983年   936篇
  1979年   1247篇
  1978年   825篇
  1977年   802篇
  1976年   753篇
  1975年   891篇
  1974年   1135篇
  1973年   1194篇
  1972年   1129篇
  1971年   1097篇
  1970年   1024篇
  1969年   1102篇
  1968年   1140篇
  1967年   991篇
  1966年   896篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
Pulmonary hypertension of the newborn (PHN) constitutes a critical condition with severe cardiovascular and neurological consequences. One of its main causes is hypoxia during gestation, and thus, it is a public health concern in populations living above 2500 m. Although some mechanisms are recognized, the pathophysiological facts that lead to PHN are not fully understood, which explains the lack of an effective treatment. Oxidative stress is one of the proposed mechanisms inducing pulmonary vascular dysfunction and PHN. Therefore, we assessed whether melatonin, a potent antioxidant, improves pulmonary vascular function. Twelve newborn sheep were gestated, born, and raised at 3600 meters. At 3 days old, lambs were catheterized and daily cardiovascular measurements were recorded. Lambs were divided into two groups, one received daily vehicle as control and another received daily melatonin (1 mg/kg/d), for 8 days. At 11 days old, lung tissue and small pulmonary arteries (SPA) were collected. Melatonin decreased pulmonary pressure and resistance for the first 3 days of treatment. Further, melatonin significantly improved the vasodilator function of SPA, enhancing the endothelial‐ and muscular‐dependent pathways. This was associated with an enhanced nitric oxide‐dependent and nitric oxide independent vasodilator components and with increased nitric oxide bioavailability in lung tissue. Further, melatonin reduced the pulmonary oxidative stress markers and increased enzymatic and nonenzymatic antioxidant capacity. Finally, these effects were associated with an increase of lumen diameter and a mild decrease in the wall of the pulmonary arteries. These outcomes support the use of melatonin as an adjuvant in the treatment for PHN.  相似文献   
32.
33.
34.
35.
The European Journal of Health Economics - The aims of this study were to assess whether there is a conceptual overlap between the questionnaires HIT-6 and EQ-5D and to develop a mapping algorithm...  相似文献   
36.

Objectives

To determine the incidence of incisional hernia (IH) in the extraction incision (EI) in colorectal resection for cancer. To analyze whether the location of the incision has any relationship with the incidence of hernias and whether mesh could be useful for prevention in high-risk patients.

Methods

Retrospective review of the colon and rectal surgery database from January 2015 to December 2016. Data were classified into 2 groups, transverse (TI) and midline incision (MI), and the latter was divided into 2 subgroups (mesh [MIM] and suture [MIS]). Patients were classified using the HERNIAscore. Hernias were diagnosed by clinical and/or CT examination.

Results

A total of 182 out of 210 surgical patients were included. After a median follow-up of 13.0 months, 39 IH (21.9%) were detected, 23 of which (13.4%) were in the EI; their frequency was lower in the TI group (3.4%) and in the MIM group (5.9%) than in the MIS group (29.5%; p = 0.007). The probability of developing IH in the MIS group showed an OR = 11.7 (95%CI: 3.3-42.0) compared to the TI group and 4.3 (IC 95%: 1.1-16.3) versus the MIM group.

Conclusions

The location of the incision is relevant to avoid incisional hernias. Transverse incisions should be used as the first option. When a midline incision is needed, a prophylactic mesh could be considered in high risk patients because it is safe and associated with low morbidity.  相似文献   
37.
38.
Clinical Oral Investigations - The aim of this study was the analysis of WNT10A variants in seven families of probands with various forms of tooth agenesis and self-reported family history of...  相似文献   
39.
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