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   19112篇
  免费   1406篇
  国内免费   39篇
耳鼻咽喉   157篇
儿科学   444篇
妇产科学   344篇
基础医学   2660篇
口腔科学   384篇
临床医学   2375篇
内科学   3681篇
皮肤病学   414篇
神经病学   1708篇
特种医学   659篇
外国民族医学   2篇
外科学   2331篇
综合类   218篇
一般理论   25篇
预防医学   2114篇
眼科学   412篇
药学   1532篇
中国医学   24篇
肿瘤学   1073篇
  2023年   99篇
  2022年   116篇
  2021年   346篇
  2020年   252篇
  2019年   332篇
  2018年   439篇
  2017年   321篇
  2016年   336篇
  2015年   406篇
  2014年   531篇
  2013年   813篇
  2012年   1210篇
  2011年   1284篇
  2010年   711篇
  2009年   692篇
  2008年   1159篇
  2007年   1237篇
  2006年   1193篇
  2005年   1222篇
  2004年   1228篇
  2003年   1058篇
  2002年   1030篇
  2001年   354篇
  2000年   358篇
  1999年   312篇
  1998年   253篇
  1997年   201篇
  1996年   164篇
  1995年   131篇
  1994年   117篇
  1993年   101篇
  1992年   214篇
  1991年   184篇
  1990年   193篇
  1989年   199篇
  1988年   165篇
  1987年   157篇
  1986年   147篇
  1985年   129篇
  1984年   113篇
  1983年   91篇
  1982年   72篇
  1981年   72篇
  1980年   56篇
  1979年   77篇
  1978年   70篇
  1977年   69篇
  1976年   56篇
  1975年   58篇
  1973年   54篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
3.

Objective

Arch obstruction after the Norwood procedure is common and contributes to mortality. We determined the prevalence, associated factors, and practice variability of arch reintervention and assessed whether arch reintervention is associated with mortality.

Methods

From 2005 to 2017, 593 neonates in the Congenital Heart Surgeons' Society Critical Left Heart Obstruction cohort underwent a Norwood procedure. Median follow-up was 3.7 years. Multivariable parametric models, including a modulated renewal analysis, were performed.

Results

Of the 593 neonates, 146 (25%) underwent 218 reinterventions for arch obstruction after the Norwood procedure: catheter-based (n = 168) or surgical (n = 50) at a median age of 4.3 months (quartile 1-quartile 3, 2.6-5.7). Interdigitation of the distal aortic anastomosis was protective against arch reintervention. Development of ≥ moderate tricuspid valve regurgitation and right ventricular dysfunction at any point was associated with arch reintervention. Nonsignificant variables for arch reintervention included shunt type and preoperative aortic measurements. Surgical arch reintervention was protective against arch reintervention, but transcatheter reintervention was associated with increased reintervention. Arch reintervention was not associated with increased mortality. There was wide institutional variation in incidence of arch reintervention (range, 0-40 reinterventions per 100 years patient follow-up) and in preintervention gradient (range, 0-64 mm Hg).

Conclusions

Interdigitation of the distal aortic anastomosis during the Norwood procedure decreased the risk of arch reintervention. Surgical arch reintervention is more definitive than transcatheter. Arch reintervention after the Norwood procedure is not associated with increased mortality. Serial surveillance for arch obstruction, integrated with changes in right ventricular function and tricuspid valve regurgitation, is recommended after the Norwood procedure to improve outcomes.  相似文献   
4.
5.
6.
Pulmonary hamartomas are usually an incidental finding and range in size from 1 cm to 8 cm in diameter in various series. We report a case of a massive pulmonary hamartoma (size 25.5 × 17.5 × 6.5 cm and weighing 1134 g) in a 61 year old male who presented with a short history of breathlessness. The tumour was arising from the medial border of the right lung and occupying most of the right chest extending in to the anterior mediastinum. The tumour was compressing the right lung and there was no evidence of infiltration into the surrounding structures. It was successfully treated by surgical resection and final histology was pulmonary hamartoma with predominantly adipose and leiomyomatous differentiation.  相似文献   
7.
8.
OBJECTIVE: Cervical nerve root stimulation (CRS) is a technique of assessing the proximal segments of motor axons destined to upper extremity muscles. Few studies report normal values. The objective was to determine CMAP onset-latencies and CMAP amplitude, area, and duration changes in healthy controls for the abductor pollicis brevis (APB), abductor digiti minimi (ADM), biceps, and riceps muscles. In addition, to determine the tolerability of CRS, as measured by the visual analog scale (VAS). METHODS: We studied 21 healthy volunteers prospectively with CRS using four target muscles (APB, ADM, biceps, and triceps) bilaterally. Collision studies were used in all APB recordings. VAS was obtained in all subjects. RESULTS: Mean CMAP onset-latencies were: APB 14 +/- 1.5 ms; ADM 14.2 +/- 1.5 ms; biceps 5.4 +/- 0.6 ms; triceps 5.4 +/- 1.0 ms. Onset-latency significantly correlated with height for all nerves. The mean change in CMAP amplitude and area (%) between most distal stimulation and CRS was: APB reduction of 15.1 +/- 11.6 and 4.9 +/- 3.6%; ADM reduction of 21.1 +/- 10.7 and 17.2 +/- 8.8; biceps reduction of 10 +/- 11.5 and reduction of 8.7 +/- 6.8; triceps increase of 3.3 +/- 5.2 and 11.0 +/- 9.9% respectively. Mean CMAP duration change between most distal stimulation and CRS was: APB, increase of 20.4 +/- 7.4%; ADM, increase of 14.4 +/- 8.5%; biceps, increase of 13.9 +/- 10.8%; triceps, increase of 7.7 +/- 6.7%. The mean VAS score was 3.8 +/- 1.2, and all subjects completed the study. CONCLUSIONS: The present study establishes normative data and indicates that CRS is a well-tolerated technique. SIGNIFICANCE: The normal values may be used as reference data for the needle CRS technique in the assessment of proximal conduction abnormalities.  相似文献   
9.
Platelet-rich fibrin (PRF) belongs to a new generation of platelet concentrates geared to simplified preparation without biochemical blood handling. In this initial article, we describe the conceptual and technical evolution from fibrin glues to platelet concentrates. This retrospective analysis is necessary for the understanding of fibrin technologies and the evaluation of the biochemical properties of 3 generations of surgical additives, respectively fibrin adhesives, concentrated platelet-rich plasma (cPRP) and PRF. Indeed, the 3-dimensional fibrin architecture is deeply dependent on artificial clinical polymerization processes, such as massive bovine thrombin addition. Currently, the slow polymerization during PRF preparation seems to generate a fibrin network very similar to the natural one. Such a network leads to a more efficient cell migration and proliferation and thus cicatrization.  相似文献   
10.
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