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   506篇
  免费   55篇
  国内免费   11篇
耳鼻咽喉   15篇
儿科学   8篇
妇产科学   3篇
基础医学   58篇
口腔科学   10篇
临床医学   54篇
内科学   155篇
皮肤病学   6篇
神经病学   33篇
特种医学   11篇
外国民族医学   1篇
外科学   61篇
综合类   12篇
预防医学   26篇
眼科学   31篇
药学   39篇
中国医学   5篇
肿瘤学   44篇
  2023年   8篇
  2022年   19篇
  2021年   27篇
  2020年   11篇
  2019年   18篇
  2018年   27篇
  2017年   5篇
  2016年   15篇
  2015年   24篇
  2014年   26篇
  2013年   34篇
  2012年   29篇
  2011年   32篇
  2010年   9篇
  2009年   21篇
  2008年   20篇
  2007年   27篇
  2006年   35篇
  2005年   24篇
  2004年   18篇
  2003年   21篇
  2002年   16篇
  2001年   15篇
  2000年   11篇
  1999年   4篇
  1998年   2篇
  1995年   7篇
  1994年   1篇
  1993年   1篇
  1992年   3篇
  1991年   3篇
  1990年   1篇
  1989年   6篇
  1988年   3篇
  1987年   9篇
  1986年   5篇
  1985年   5篇
  1984年   1篇
  1983年   3篇
  1982年   4篇
  1981年   2篇
  1980年   3篇
  1979年   3篇
  1978年   3篇
  1977年   1篇
  1973年   3篇
  1971年   1篇
  1970年   1篇
  1968年   1篇
  1936年   1篇
排序方式: 共有572条查询结果,搜索用时 15 毫秒
11.
12.
13.
14.
Aim: To study hepatitis C virus (HCV) selection and hypervariable region-1 (HVR1) evolution in a chimpanzee chronically infected with HCV-1 over 12 years after inoculation with a human factor VIII concentrate contaminated with HCV. Methods: From the inoculum, the earliest chimpanzee plasma and 12 annual plasma samples, HCV fragments including HVR1 were amplified followed by cloning and sequencing. Results: Five HCV subtypes - 1a, 1b, 2a, 2b, 3a - and multiple 1a strains were identified in the inoculum. Two 1a strains were found in the earliest chimpanzee sample, while a single HCV-1 strain was detected in the 12 annual samples. None of the chimpanzee sequences were identical to those found in the inoculum. Over 12 years, HVR1 patterns changed irregularly, but a few patterns showed identical nucleotide or amino acid sequences. In the last three years, the variety of HVR1 patterns decreased, while the proportion of major patterns increased. These corresponded to a higher virus load and a lower number of amino acid substitutions. Simultaneously, the HVR1 sequences became more similar to the consensus sequence of the 1a subtype. Conclusion: HCV selection was observed from the inoculum to the inoculated chimpanzee and from the early acute hepatitis to the persistent chronic infection. The selection occurred at three levels: among subtypes after transmission, among isolates during acute hepatitis and among quasispecies in chronic infection.  相似文献   
15.
16.

Background

General practice receptionists fulfil an essential role in UK primary care, shaping patient access to health professionals. They are often portrayed as powerful ‘gatekeepers’. Existing literature and management initiatives advocate more training to improve their performance and, consequently, the patient experience.

Aim

To explore the complexity of the role of general practice receptionists by considering the wider practice context in which they work.

Design and setting

Ethnographic observation in seven urban general practices in the north-west of England.

Method

Seven researchers conducted 200 hours of ethnographic observation, predominantly in the reception areas of each practice. Forty-five receptionists were involved in the study and were asked about their work as they carried out their activities. Observational notes were taken. Analysis involved ascribing codes to incidents considered relevant to the role and organising these into related clusters.

Results

Receptionists were faced with the difficult task of prioritising patients, despite having little time, information, and training. They felt responsible for protecting those patients who were most vulnerable, however this was sometimes made difficult by protocols set by the GPs and by patients trying to ‘play’ the system.

Conclusion

Framing the receptionist–patient encounter as one between the ‘powerful’ and the ‘vulnerable’ gets in the way of fully understanding the complex tasks receptionists perform and the contradictions that are inherent in their role. Calls for more training, without reflective attention to practice dynamics, risk failing to address systemic problems, portraying them instead as individual failings.  相似文献   
17.
In this paper we present a fully automated graph-based segmentation algorithm that jointly uses optical coherence tomography (OCT) and OCT angiography (OCTA) data to segment Bruch’s membrane (BM). This is especially valuable in cases where the spatial correlation between BM, which is usually not visible on OCT scans, and the retinal pigment epithelium (RPE), which is often used as a surrogate for segmenting BM, is distorted by pathology. We validated the performance of our proposed algorithm against manual segmentation in a total of 18 eyes from healthy controls and patients with diabetic retinopathy (DR), non-exudative age-related macular degeneration (AMD) (early/intermediate AMD, nascent geographic atrophy (nGA) and drusen-associated geographic atrophy (DAGA) and geographic atrophy (GA)), and choroidal neovascularization (CNV) with a mean absolute error of ∼0.91 pixel (∼4.1 μm). This paper suggests that OCT-OCTA segmentation may be a useful framework to complement the growing usage of OCTA in ophthalmic research and clinical communities.  相似文献   
18.
19.
20.

Introduction

Diabetes mellitus (DM) afflicts at least 5 million people in Nigeria, with more than 80% having type 2 diabetes mellitus (T2DM). Microvascular complications increase both morbidity and mortality inpatients with T2DM. The aims of this study were to report the burden of various microvascular complications in T2DM and to identify various factors associated with these complications in patients with T2DM attending the diabetes outpatients'' clinic.

Methods

Ninety (90) patients with T2DM who have attended diabetes clinic for at least 3 months were recruited for this study. Detailed history, physical examination and biochemical analysis was done in each of the patients. All patients underwent a detailed standard evaluation to detect diabetic retinopathy (fundoscopy), neuropathy (10g monofilament and/or diabetes neuropathy scores), and nephropathy (microalbuminuria, macroalbuminuria, serum creatinine and estimated glomerular filtration rate).

Results

There was high prevalence of microvascular complications among patients with T2DM. Almost half of patients with T2DM had some form of microvascular complications; diabetic neuropathy being the commonest (69.6%),followed by nephropathy (54.5%) and retinopathy (48.9%). The factors associated with developing these complications were increasing age, duration of diabetes, hypertension and dyslipidaemia for nephropathy and neuropathy.

Conclusion

There is a high burden of microvascular complications in patients with type 2 diabetes. Age, male gender, hypertension, glycaemic control, BMI and duration of diabetes, and glycaemic control were factors associated with microvasular complications.  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