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   20419篇
  免费   1216篇
  国内免费   81篇
耳鼻咽喉   123篇
儿科学   857篇
妇产科学   485篇
基础医学   2691篇
口腔科学   341篇
临床医学   1838篇
内科学   4358篇
皮肤病学   458篇
神经病学   1791篇
特种医学   533篇
外科学   2695篇
综合类   204篇
一般理论   19篇
预防医学   1446篇
眼科学   430篇
药学   1470篇
中国医学   32篇
肿瘤学   1945篇
  2023年   207篇
  2022年   347篇
  2021年   686篇
  2020年   396篇
  2019年   604篇
  2018年   666篇
  2017年   500篇
  2016年   515篇
  2015年   610篇
  2014年   848篇
  2013年   1028篇
  2012年   1613篇
  2011年   1563篇
  2010年   885篇
  2009年   755篇
  2008年   1288篇
  2007年   1230篇
  2006年   1196篇
  2005年   1105篇
  2004年   1063篇
  2003年   965篇
  2002年   799篇
  2001年   196篇
  2000年   202篇
  1999年   241篇
  1998年   143篇
  1997年   139篇
  1996年   124篇
  1995年   94篇
  1994年   77篇
  1993年   88篇
  1992年   144篇
  1991年   139篇
  1990年   94篇
  1989年   110篇
  1988年   93篇
  1987年   93篇
  1986年   87篇
  1985年   112篇
  1984年   68篇
  1983年   58篇
  1982年   37篇
  1981年   29篇
  1980年   29篇
  1979年   36篇
  1977年   31篇
  1974年   35篇
  1973年   43篇
  1972年   34篇
  1968年   27篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
2.
BackgroundLittle is known about the extent of ordering low-value services by.PurposeTo compare the rates of low-value back images ordered by primary care physicians (PCMDs) and primary care nurse practitioners (PCNPs).MethodWe used 2012 and 2013 Medicare Part B claims for all beneficiaries in 18 hospital referral ?regions (HRRs) and a measure of low-value back imaging from Choosing Wisely. Models included random clinician effect and fixed effects for beneficiary age, disability, Elixhauser comorbidities, clinician sex, the emergency department setting, back pain visit volume, organization, and region (HRR).FindingsPCNPs (N = 231) and PCMDs (N = 4,779) order low-value back images at similar rates (NP: all images: 26.5%; MRI/CT: 8.4%; MD: all images: 24.5%; MRI/CT: 7.7%), with no detectable significant difference when controlling for covariates.DiscussionPCNPs and PCMDs order low-value back images at an effectively similar rate.  相似文献   
3.
4.
5.
6.

Background

In the emergency department, rib fractures are a common finding in patients who sustain chest trauma. Rib fractures may be a sign of significant, underlying pathology, especially in the elderly patients where rib fractures are associated with significant morbidity and mortality. To date, no studies have evaluated the ability of ultrasound to detect rib fractures using cadaver models and subsequently use this model as a teaching tool.

Objectives

The purpose of this study was to determine if it is possible to generate rib fractures on cadaver models which could be accurately identified using ultrasound.

Methods

This was a cross-sectional study performed during one session at a cadaver lab. A single hemithorax from four adult cadavers were used as models. Single rib fractures on each of rib five through eight were created. Four subjects, blinded to the normal versus fractured ribs, were asked to identify the presence of a fracture on each rib.

Results

A total of 8 of 16 potential ribs had fractured induced by study staff. Mean accuracy was 55% for all subjects. The overall sensitivity and specificity for detecting rib fractures was 50% (CI: 31.89–68.11) and 59.38% (CI: 35.69–73.55) respectively. The overall PPV and NPV was 55.17% and 54.29% respectively.

Conclusions

In this pilot study, subjects were not able to detect induced rib fractures using ultrasound on cadaver models. The use of this model as a teaching tool in the detection of rib fractures requires further investigation.  相似文献   
7.
8.
9.
We report on 3 patients with pseudoathetosis, which are involuntary, slow, writhing movements due to loss of proprioception.  相似文献   
10.
The aim of this study was to determine whether patients with sickle cell disease (SCD) in steady state had pulmonary abnormalities seen on high-resolution computed tomography (HRCT) and whether any abnormalities correlated with contemporaneously diagnosed lung function abnormalities. A subsidiary question was whether the results of a noninvasive measure of haemolysis (end-tidal carbon monoxide (ETCO) levels) correlated with pulmonary function abnormalities. Thirty three patients with SCD, median (range) age 36 yrs (17-67 yrs) were examined. The degree of lobar volume loss and ground-glass opacification and prominence of central vessels on HRCT were quantitatively assessed. Pulmonary function was assessed by measurements of lung volumes, spirometry, gas transfer and oxygen saturation. ETCO levels were measured using an end-tidal CO monitor. Forced expiratory volume in one second (FEV1), forced vital capacity and total lung capacity significantly correlated with HRCT findings, particularly lobar volume loss. ETCO levels significantly negatively correlated with FEV1, vital capacity measured using a plethysmograph, specific airway conductance and arterial oxygen saturation measured by pulse oxymetry. In conclusion, the present results suggest that high-resolution computed tomography noninvasive assessment of haemolysis might be useful to identify sickle cell disease patients with respiratory function impairment.  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