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   6638篇
  免费   367篇
  国内免费   26篇
耳鼻咽喉   50篇
儿科学   98篇
妇产科学   106篇
基础医学   851篇
口腔科学   152篇
临床医学   554篇
内科学   2045篇
皮肤病学   125篇
神经病学   577篇
特种医学   160篇
外科学   940篇
综合类   63篇
一般理论   1篇
预防医学   468篇
眼科学   165篇
药学   390篇
中国医学   10篇
肿瘤学   276篇
  2024年   6篇
  2023年   39篇
  2022年   94篇
  2021年   235篇
  2020年   106篇
  2019年   163篇
  2018年   234篇
  2017年   117篇
  2016年   194篇
  2015年   178篇
  2014年   268篇
  2013年   316篇
  2012年   514篇
  2011年   535篇
  2010年   326篇
  2009年   279篇
  2008年   426篇
  2007年   489篇
  2006年   458篇
  2005年   385篇
  2004年   388篇
  2003年   315篇
  2002年   308篇
  2001年   41篇
  2000年   36篇
  1999年   39篇
  1998年   60篇
  1997年   47篇
  1996年   35篇
  1995年   32篇
  1994年   28篇
  1993年   41篇
  1992年   32篇
  1991年   20篇
  1990年   14篇
  1989年   12篇
  1988年   17篇
  1987年   9篇
  1986年   9篇
  1984年   19篇
  1983年   20篇
  1982年   19篇
  1981年   21篇
  1980年   13篇
  1979年   6篇
  1978年   7篇
  1977年   16篇
  1976年   9篇
  1974年   11篇
  1969年   6篇
排序方式: 共有7031条查询结果,搜索用时 0 毫秒
81.
The objective of this study is to establish whether there is an association between the presence of FCGR3A V(176) polymorphism with SLE or its manifestations. We included 94 patients according to the 1982 ACR criteria as well as 98 controls matched by age and gender. The 11 ACR diagnostic criteria were analyzed on the clinical files. The polymorphism FCGR3A V(176) was determined by direct sequencing. There was not an association between the polymorphism FCGR3A V(176) with SLE or its main manifestations. The allelic frequency for F(176) was: 0.80 and 0.72 in cases and controls, respectively (P?=?0.09, IC95%: 0.42?C1.07); and the genotypic frequency in the group of cases was: 0.65 for homozygotes F(176)/F(176), 0.30 for heterozygotes and 0.05 for the homozygotes V(176)/V(176), while for the control group it was 0.53, 0.39 and 0.08, respectively. The polymorphism FCGR3A V(176) is not associated with SLE or any of its manifestations in patients with SLE from the West of Mexico.  相似文献   
82.
83.
84.
85.

Introduction

Invasive respiratory support is a cornerstone of Critical Care Medicine, however, protocols for withdrawal of mechanical ventilation are still far from perfect. Failure to extubation occurs in up to 20% of patients, despite a successful spontaneous breathing trial (SBT).

Methods

We prospectively included ventilated patients admitted to medical and surgical intensive care unit in a university hospital in northern Mexico. At the end of a successful SBT, we measured diaphragmatic shortening fraction (DSF) by the formula: diaphragmatic thickness at the end of inspiration – diaphragmatic thickness at the end of expiration/diaphragmatic thickness at the end of expiration × 100, and the presence of B-lines in five regions of the right and left lung. The primary objective was to determine whether analysis of DSF combined with pulmonary ultrasound improves prediction of extubation failure.

Results

Eighty-two patients were included, 24 (29.2%) failed to extubation. At univariate analysis, DSF (Youden's J: >30% [sensibility and specificity 62 and 50%, respectively]) and number of B-lines regions (Youden's J: >1 zone [sensibility and specificity 66 and 92%, respectively]) were significant related to extubation failure (area under the curve 0.66 [0.52–0.80] and 0.81 [0.70–0.93], respectively). At the binomial logistic regression, only the number of B-lines regions remains significantly related to extubation failure (OR 5.91 [2.33–14.98], P < .001).

Conclusion

In patients with a successfully SBT, the absence of B-lines significantly decreases the probability of extubation failure. Diaphragmatic shortening fraction analysis does not add predictive power over the use of pulmonary ultrasound.  相似文献   
86.

Introduction

New digital thoracic drainage systems allow an objective measurement of air leakage. They have proven their usefulness in the postoperative thoracic surgery in adults, but there is little experience with its use in the pediatric population. The objective of our study is to analyze their safety and effectiveness in the postoperative period of the pediatric patients.

Method

A prospective consecutive observational study was done. All patients submitted to pulmonary resection between 2011 and 2017 and in whom digital thoracic drainage system was used (Thopaz Chest Drain System, Medela, Switzerland) were prospectively enrolled in this study. We analyzed variables: duration of chest tube (CT), days of hospitalization and radiographs in the immediate postoperative period related to the presence of CT. This group was compared with a historical cohort of patients (from 2011 to 2015) with a pulmonary resection in whom the traditional thoracic drainage was used. For the statistical analysis, the Mann–Whitney U-Test was used for independent samples.

Result

Twenty-six patients were included, Digital drainage system was used in13 patients and traditional drainage was used in 13 patients. The median age was 18?months (12?days-14?years). The mean number of days with the chest tube was 1.69?±?0.6 in digital drainage group versus 5.38?±?4?days in traditional drainage group (p?<?0.05) The mean number of postoperative radiographs was 2.8?±?1.1 in digital drainage group versus 6.23?±?5.2 radiographs in traditional drainage group (p?<?0.05). The average hospital stay in digital drainage group was 5.69?±?2.7?days versus 7?±?4.7?days in the traditional drainage group (p?>?0.05). No complications related to the use of digital drainage group were registered.

Conclusion

The digital thoracic drainage systems provide an objective measurement of air leakage, allowing early chest tube removal and decreasing the number of radiographs performed postoperatively. Its use in the pediatric population appears to be safe and potentially beneficial.

Level of evidence

II.  相似文献   
87.
88.
89.
90.
Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disorder that almost exclusively involves motor neurons although autonomic dysfunction has also been reported. We present an 84-year-old female with no documented history of heart disease, who was admitted with negative T waves in the electrocardiogram precordial leads mimicking myocardial ischaemia. No other abnormalities were shown in the rest of the cardiologic evaluation, suggesting autonomic nervous system dysfunction. A neurophysiological study demonstrated acute and chronic denervation in multiple muscles with normal nerve conduction studies, confirming ALS diagnosis. Previous studies have shown that subclinical sympathetic hyperfunction and parasympathetic hypofunction might result in cardiovascular dysfunction in ALS patients. It is important to detect disturbances of autonomic cardiac control because this dysfunction may influence survival and quality of life, leading to a decrease in life expectancy in ALS patients. This Case Report may support the impairment of cardiac autonomic control in patients with ALS.  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