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   156145篇
  免费   7165篇
  国内免费   499篇
耳鼻咽喉   2605篇
儿科学   4647篇
妇产科学   3569篇
基础医学   21143篇
口腔科学   5587篇
临床医学   9870篇
内科学   38174篇
皮肤病学   5041篇
神经病学   12679篇
特种医学   3524篇
外国民族医学   2篇
外科学   18794篇
综合类   997篇
一般理论   43篇
预防医学   15346篇
眼科学   3373篇
药学   11064篇
中国医学   884篇
肿瘤学   6467篇
  2023年   1010篇
  2022年   1692篇
  2021年   4214篇
  2020年   2096篇
  2019年   3977篇
  2018年   5726篇
  2017年   3386篇
  2016年   3243篇
  2015年   3642篇
  2014年   4853篇
  2013年   6960篇
  2012年   10938篇
  2011年   11763篇
  2010年   6179篇
  2009年   4814篇
  2008年   9079篇
  2007年   9583篇
  2006年   8873篇
  2005年   8854篇
  2004年   7910篇
  2003年   7335篇
  2002年   6799篇
  2001年   4441篇
  2000年   5000篇
  1999年   3925篇
  1998年   844篇
  1997年   643篇
  1996年   540篇
  1995年   475篇
  1994年   383篇
  1993年   307篇
  1992年   1513篇
  1991年   1260篇
  1990年   1135篇
  1989年   937篇
  1988年   825篇
  1987年   757篇
  1986年   759篇
  1985年   652篇
  1984年   466篇
  1983年   395篇
  1979年   440篇
  1975年   304篇
  1974年   390篇
  1973年   390篇
  1972年   335篇
  1971年   365篇
  1970年   326篇
  1969年   351篇
  1968年   311篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
32.
33.
34.
35.
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   
36.
37.
38.
39.

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   
40.
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   
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