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   443篇
  免费   13篇
  国内免费   15篇
儿科学   45篇
妇产科学   3篇
基础医学   30篇
口腔科学   6篇
临床医学   42篇
内科学   107篇
皮肤病学   5篇
神经病学   5篇
特种医学   128篇
外科学   22篇
综合类   44篇
预防医学   8篇
药学   11篇
肿瘤学   15篇
  2021年   2篇
  2020年   1篇
  2019年   2篇
  2018年   5篇
  2017年   2篇
  2016年   1篇
  2015年   3篇
  2014年   5篇
  2013年   10篇
  2012年   4篇
  2011年   4篇
  2010年   7篇
  2009年   13篇
  2008年   2篇
  2007年   9篇
  2006年   8篇
  2005年   10篇
  2004年   3篇
  2003年   5篇
  2002年   3篇
  2001年   1篇
  2000年   9篇
  1999年   10篇
  1998年   24篇
  1997年   39篇
  1996年   45篇
  1995年   23篇
  1994年   26篇
  1993年   26篇
  1992年   6篇
  1991年   4篇
  1990年   8篇
  1989年   18篇
  1988年   21篇
  1987年   14篇
  1986年   21篇
  1985年   7篇
  1984年   6篇
  1983年   7篇
  1982年   11篇
  1981年   5篇
  1980年   8篇
  1979年   2篇
  1978年   8篇
  1977年   6篇
  1976年   11篇
  1975年   6篇
排序方式: 共有471条查询结果,搜索用时 0 毫秒
21.
Malignant uveal melanoma and simulating lesions: MR imaging evaluation   总被引:7,自引:0,他引:7  
Twenty-one patients with intraocular disease were studied by magnetic resonance (MR) imaging and computed tomography (CT). In 13 cases, malignant uveal melanoma was considered the likely diagnosis. Both imaging methods were accurate in determining the location and size of uveal melanomas. MR imaging was superior for the assessment of possible associated retinal detachment, for assessment of vitreous change, and for differentiating uveal melanoma from choroidal hemangioma and choroidal detachment. A case of retinal gliosis could not be differentiated from uveal melanoma by either technique. Uveal melanomas appeared as hyperintense lesions on T1-weighted images and as hypointense lesions on T2-weighted images. High signal intensity of the vitreous was observed in patients with vitritis and in those who were thought to have protein leaking into the vitreous as a result of impairment of the retinal-blood barrier.  相似文献   
22.

Introduction

The acute surgical model has been trialled in several institutions with mixed results. The aim of this study was to determine whether the acute surgical model provides better outcomes for patients with acute biliary presentation, compared with the traditional emergency surgery model of care.

Methods

A retrospective review was carried out of patients who were admitted for management of acute biliary presentation, before and after the establishment of an acute surgical unit (ASU). Outcomes measured were time to operation, operating time, after-hours operation (6pm – 8am), length of stay and surgical complications.

Results

A total of 342 patients presented with acute biliary symptoms and were managed operatively. The median time to operation was significantly reduced in the ASU group (32.4 vs 25.4 hours, p=0.047), as were the proportion of operations performed after hours (19.5% vs 2.5%, p<0.001) and the median length of stay (4 vs 3 days, p<0.001). The median operating time, rate of conversion to open cholecystectomy and wound infection rates remained similar.

Conclusions

Implementation of an ASU can lead to objective differences in outcomes for patients who present with acute cholecystitis. In our study, the ASU significantly reduced time to operation, the number of operations performed after hours and length of stay.  相似文献   
23.
The long‐term benefits of habitual physical activity during adolescence on adult bone structure and strength are poorly understood. We investigated whether physically active adolescents had greater bone size, density, content, and estimated bone strength in young adulthood when compared to their peers who were inactive during adolescence. Peripheral quantitative computed tomography (pQCT) was used to measure the tibia and radius of 122 (73 females) participants (age mean ± SD, 29.3 ± 2.3 years) of the Saskatchewan Pediatric Bone Mineral Accrual Study (PBMAS). Total bone area (ToA), cortical density (CoD), cortical area (CoA), cortical content (CoC), and estimated bone strength in torsion (SSIp) and muscle area (MuA) were measured at the diaphyses (66% tibia and 65% radius). Total density (ToD), trabecular density (TrD), trabecular content (TrC), and estimated bone strength in compression (BSIc) were measured at the distal ends (4%). Participants were grouped by their adolescent physical activity (PA) levels (inactive, average, and active) based on mean PA Z‐scores obtained from serial questionnaire assessments completed during adolescence. We compared adult bone outcomes across adolescent PA groups in each sex using analysis of covariance followed by post hoc pairwise comparisons with Bonferroni adjustments. When adjusted for adult height, MuA, and PA, adult males who were more physically active than their peers in adolescence had 13% greater adjusted torsional bone strength (SSIp, p < 0.05) and 10% greater adjusted ToA (p < 0.05) at the tibia diaphysis. Females who were more active in adolescence had 10% larger adjusted CoA (p < 0.05), 12% greater adjusted CoC (p < 0.05) at the tibia diaphysis, and 3% greater adjusted TrC (p < 0.05) at the distal tibia when compared to their inactive peers. Benefits to tibia bone size, content, and strength in those who were more active during adolescence seemed to persist into young adulthood, with greater ToA and SSIp in males, and greater CoA, CoC, and TrC in females. © 2014 American Society for Bone and Mineral Research.  相似文献   
24.
Knotting of intravascular catheters is an uncommon but a well‐recognized occurrence. The Swan–Ganz catheter (SGC) is the one that knots most commonly. A case of a knotted SGC is described in a patient with a persistent left‐sided superior vena cava, and we propose that the presence of a left‐sided superior vena cava is a risk factor for knot formation not previously reported. We review the published work on the risk factors for knot formation and on the techniques used to remove knotted SGC. We describe a technique using a gooseneck snare and Omni Flush catheter (Angiodynamics, Queensbury, NY, USA) to loosen and untie a knotted SGC.  相似文献   
25.
Background Patients with prostate cancer with a pre-operative prostate-specific antigen (PSA) τ;15ng/ml who undergo radical retropubic prostatectomy (RRP) generally do not have a good outcome, yet may have organ-confined cancer and should be offered the option of surgery. Aim To assess the outcome of patients who underwent RRP with a pre-operative PSA ≥ 15ng/ml. Methods Thirty-four patients, mean pre-operative PSA: 25.46ng/ml (15.03–76.6) and mean Gleason score: 6.4 (5–9) were assessed. Results Two groups were identified. Group I: 41% (14/34) have no biochemical recurrence to mean follow up of 58 months (30–106). Mean PSA: 18.8ng/ml (15.03–25.84). Mean Gleason score: 6.1 (5–7). Clinical stage: T1c in 80%. No patient had seminal vesicle or lymph node involvement. Group II: 59% (20/34) have biochemical recurrence or died (3) from their disease to mean follow up of 66 months (36–98). Mean PSA: 28.9ng/ml (15.28–76.6). Mean Gleason score: 6.7 (5–9). Clinical stage: T1c in 25%. Eleven patients had seminal vesicle (8) involvement or positive lymph nodes (3) or both (2). Conclusion RRP seems feasible in patients whose pre-operative PSA is between 15 and 25ng/ml with stage T1c, Gleason score ≤ 7 and negative lymph node frozen section.  相似文献   
26.
This study evaluated the accuracy of the interpretation of the chest film in delineating localised abnormalities of ventilation and perfusion, as well as the overall severity of airways obstruction, exercise tolerance, and clinical condition in children with cystic fibrosis. Radiographic findings in various regions of the chest film were compared with the functional values obtained with regional lung function tests which evaluated the arrival and disappearance of boluses of radioactive nitrogen given by inhalation and infusion. While the more severely affected areas on the chest radiograph were found to correlate with similar regions on the lung function tests, as did overall scores, errors occurred in some cases if the x-ray film alone was used as a judge of regional physiological derangement. In addition the degree of airways obstruction, the exercise tolerance on a cycle ergometer, and clinical grading, each correlated significantly with the radiographic score. We conclude that the chest radiograph is a good indicator of the overall severity of the lung disease and that it correlates well with exercise tolerance and clinical condition in cystic fibrosis.  相似文献   
27.
急性有机磷农药中毒120例的救治   总被引:1,自引:0,他引:1  
0 引言 近年来 ,我科在救治急性有机磷农药 (organophos-phorus,OP)中毒方面 ,积累了一些经验 ,现报告如下 .1 对象和方法1 .1 对象 本组 1 2 0例符合《急诊急救学》中的诊断标准 [1 ](男 2 9例 ,女 91例 ) ,年龄 1 .5~ 70岁 ,平均 2 8.6岁 .经口中毒 99例 ,经皮肤中毒 2 1例 .轻度中毒 1 5例 ,中度中毒 42例 ,重度 (含极重度 )中毒 6 3例 . 1 996年 39例 ,1 997年 43例 ,1 998年 38例 . DDV 79例 ,乐果 2 0例 ,混合性中毒 1 0例 ,水胺磷 3例 ,氧化乐果、 391 1、 1 0 5 9、对硫磷各 2例 ,敌百虫 1例 ,药名不详 1 0例 .服毒量 >2 5 …  相似文献   
28.

Objective

To investigate age and sex differences in the utilisation of hospital services for ischaemic heart disease.

Design

Analysis of routine mortality data and hospital activity data.

Setting

South West Thames Regional Health Authority.

Subjects

Residents of the South West Thames Regional Health Authority who in 1991 either died from ischaemic heart disease or were admitted to an NHS hospital in England and Wales with a main diagnosis of ischaemic heart disease.

Main outcome measures

Ratio of consultant episodes to deaths from ischaemic heart disease (as a proxymeasure of the utilisation of hospital care), and the percentages of consultant episodes in which further investigation (angiography or catheterisation) or revascularisation treatment (coronary artery bypass grafting or angioplasty) were carried out.

Results

The ratio of episodes to deaths was similar in men and women (odds ratio for men vs. women 0.96, 95% confidence intervals 0.90 to 1.03). The percentage of episodes in which further investigation was carried out was higher in men than women (odds ratio for men vs. women 1.46, 95% confidence intervals 1.25 to 1.70) as was the percentage of episodes in which revascularisation treatment was carried out (odds ratio for men vs. women 1.46, 95% confidence intervals 1.20 to 1.77). The ratio of episodes to deaths, the percentage of episodes in which further investigation was carried out, and the percentage of episodes in which revascularisation treatment was carried out all declined with age (all p values <0.001).

Conclusions

Women with ischaemic heart disease are as likely as men to be admitted to hospital, but afteradmission are less likely to undergo further investigation and revascularisation treatment. Elderly patients with ischaemic heart disease are less likely than younger patients to be admitted to hospital; after admission, they are also less likely to undergo further investigation and revascularisation treatment. Further research is needed to determine whether these age and sex differences in the use of hospital services are clinically justified.  相似文献   
29.
30.
The authors present the radiographic features of a previously incompletely delineated bone dysplasia, which they call spondylometaphyseal dysplasia, corner fracture type. This is a dominant heritable condition associated with short stature and developmental coxa vara. The progressive hip deformity usually causes significant disability requiring surgical correction. Developmental coxa vara, simulated corner fractures of long tubular bones, and vertebral body abnormalities result in a diagnostic constellation. Knowledge of these distinctive radiologic features allows accurate diagnosis, which in turn should lead to appropriate genetic counseling and possibly to earlier, more efficacious surgical treatment of the coxa vara.  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