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   2713652篇
  免费   194734篇
  国内免费   7915篇
耳鼻咽喉   36427篇
儿科学   89792篇
妇产科学   74814篇
基础医学   382640篇
口腔科学   74008篇
临床医学   244768篇
内科学   539153篇
皮肤病学   65800篇
神经病学   225460篇
特种医学   106749篇
外国民族医学   752篇
外科学   406537篇
综合类   51367篇
现状与发展   5篇
一般理论   998篇
预防医学   202563篇
眼科学   60367篇
药学   197131篇
  8篇
中国医学   5627篇
肿瘤学   151335篇
  2021年   21598篇
  2019年   22148篇
  2018年   31757篇
  2017年   24554篇
  2016年   28945篇
  2015年   32525篇
  2014年   43809篇
  2013年   65105篇
  2012年   87313篇
  2011年   91485篇
  2010年   55203篇
  2009年   52684篇
  2008年   85640篇
  2007年   91122篇
  2006年   92839篇
  2005年   89241篇
  2004年   85650篇
  2003年   82807篇
  2002年   79898篇
  2001年   131393篇
  2000年   134212篇
  1999年   113234篇
  1998年   32477篇
  1997年   28895篇
  1996年   28971篇
  1995年   28066篇
  1994年   25649篇
  1993年   23946篇
  1992年   86409篇
  1991年   82814篇
  1990年   80051篇
  1989年   77278篇
  1988年   70555篇
  1987年   69019篇
  1986年   64552篇
  1985年   61487篇
  1984年   45714篇
  1983年   38616篇
  1982年   22941篇
  1981年   20428篇
  1979年   39856篇
  1978年   28097篇
  1977年   23810篇
  1976年   22003篇
  1975年   23555篇
  1974年   27538篇
  1973年   26063篇
  1972年   24437篇
  1971年   22627篇
  1970年   20777篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
To determine percent of patients without malignancy and ≤ 40 years of age with high cumulative radiation doses through recurrent CT exams and assess imaging appropriateness. From the cohort of patients who received cumulative effective dose (CED) of ≥ 100 mSv over a 5-year period, a sub-set was identified with non-malignant disease. The top 50 clinical indications leading to multiple CTs were determined. Clinical decision support (CDS) system scores were analyzed using a widely adopted standard of 1–3 (red) as “not usually appropriate,” 4–6 (yellow) “may or may not be appropriate,” and 7–9 (green) “usually appropriate.” Clinicians reviewed patient records to assess compliance with appropriate use criteria (AUC). 9.6% of patients in our series were with non-malignant conditions and 1.4% with age ≤ 40 years. CDS scores (rounded) were 2% red, 38% yellow, 27% green, and 33% unscored CTs. Clinical society guidelines for CT exams, wherever available, were followed in 87.5 to 100% of cases. AUCs were not available for several clinical indications as also referral guidelines for serial CT imaging. More than half of CT exams were unrelated to follow-up of a primary chronic disease. We are faced with a situation wherein patients in age ≤ 40 years require or are thought to require many CT exams over the course of a few years but the radiation risk creates concern. There is a fair number of conditions for which AUC are not available. Suggested solutions include development of CT scanners with lesser radiation dose and further development of appropriateness criteria.  相似文献   
62.
63.
64.
65.
66.
67.

Introduction

Compression fractures of the cuboid bone in children and adolescents are rare. Fracture morphology, associated lesions, treatment options and long-term outcomes of this very rare injury are published in a few case reports. This study with review of the literature aims to support the understanding of fracture pattern and optimize pathways of decision making.

Material and Methods

A retrospective two-center study was performed in a patient cohort treated between 2001 and 2016. All patients aged less than 18 years who sustained a cuboid fracture were included. Age, gender, mechanism of injury, fracture morphology, amount of displacement, associated injuries, and therapy were analyzed. In the follow-up (FU), the AOFAS Midfoot Scale was investigated.

Results

Fractures of the cuboid bone were diagnosed in 7 boys and 9 girls. The mean age of the patients was 10 years (range: 2.2–16.1 years). According to the classification of Fenton we detected 11 (69%) type 2, 2 (12%) type 3 and 3 (19%) type 5b fractures. Other fracture types according to Fenton were not observed. All children under 10 years sustained a type 2 fracture. Open reduction and internal fixation was performed in 5 (31%) patients. Bone grafting was not necessary. FU was performed in 14/16 patients on average after 9 years (mean; range: 1.4–16.2 years). The mean AOFAS Midfoot Scale at FU for extra-articular type 2 fractures was 100 points, whereas in intra-articular fractures (Type 3) and fractures associated with mid-tarsal disruption (type 5b) worse results were found (95 and 66 points, accordingly).

Conclusion

This rare injury shows inhomogenous morphologies and offers different treatment approaches. Extra-articular Fenton type 2 lesions are the most common type of cuboid fracture in children (69%). A potential loss of length of the lateral column must be considered. In contrast to adults, type 1, 4, and 5a fractures were not found in our cohort of children and adolescents. Lower scores of the AOFAS Midfoot Scale were found with either intra-articular involvement or associated midfoot lesions.  相似文献   
68.

Objectives

Expedient extubation after cardiac surgery has been associated with improved outcomes, leading to postoperative extubation frequently during overnight hours. However, recent evidence in a mixed medical-surgical intensive care unit population demonstrated worse outcomes with overnight extubation. This study investigated the impact of overnight extubation in a statewide, multicenter Society of Thoracic Surgeons database.

Methods

Records from 39,812 patients undergoing coronary artery bypass grafting or valve operations (2008-2016) and extubated within 24 hours were stratified according to extubation time between 06:00 and 18:00 (day) or between 18:00 and 6:00 (overnight). Outcomes including reintubation, mortality, and composite morbidity-mortality were evaluated using hierarchical regression models adjusted for Society of Thoracic Surgeons predictive risk scores. To further analyze extubation during the night, a subanalysis stratified patients into 3 groups: 06:00 to 18:00, 18:00 to 24:00, and 24:00 to 06:00.

Results

A total of 20,758 patients were extubated overnight (52.1%) and were slightly older (median age 66 vs 65 years, P < .001) with a longer duration of ventilation (4 vs 7 hours, P < .001). Day and overnight extubation were associated with equivalent operative mortality (1.7% vs 1.7%, P = .880), reintubation (3.7% vs 3.4%, P = .141), and composite morbidity-mortality (8.2% vs 8.0%, P = .314). After risk adjustment, overnight extubation was not associated with any difference in reintubation, mortality, or composite morbidity-mortality. On subanalysis, those extubated between 24:00 and 06:00 exhibited increased composite morbidity-mortality (odds ratio, 1.18; P = .001) but no difference in reintubation or mortality.

Conclusions

Extubation overnight was not associated with increased mortality or reintubation. These results suggest that in the appropriate clinical setting, it is safe to routinely extubate cardiac surgery patients overnight.  相似文献   
69.
70.
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