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   752篇
  免费   38篇
  国内免费   12篇
耳鼻咽喉   6篇
儿科学   62篇
妇产科学   18篇
基础医学   100篇
口腔科学   39篇
临床医学   67篇
内科学   145篇
皮肤病学   9篇
神经病学   25篇
特种医学   83篇
外科学   47篇
综合类   24篇
预防医学   69篇
眼科学   4篇
药学   57篇
中国医学   1篇
肿瘤学   46篇
  2022年   4篇
  2020年   6篇
  2019年   10篇
  2018年   14篇
  2017年   11篇
  2016年   6篇
  2015年   8篇
  2014年   17篇
  2013年   23篇
  2012年   16篇
  2011年   15篇
  2010年   28篇
  2009年   24篇
  2008年   27篇
  2007年   26篇
  2006年   30篇
  2005年   23篇
  2004年   23篇
  2003年   30篇
  2002年   6篇
  2001年   20篇
  2000年   24篇
  1999年   25篇
  1998年   33篇
  1997年   24篇
  1996年   23篇
  1995年   19篇
  1994年   16篇
  1993年   13篇
  1992年   12篇
  1991年   11篇
  1990年   16篇
  1989年   18篇
  1988年   22篇
  1987年   17篇
  1986年   17篇
  1985年   20篇
  1984年   10篇
  1983年   9篇
  1982年   8篇
  1981年   8篇
  1980年   7篇
  1979年   16篇
  1978年   11篇
  1977年   6篇
  1976年   11篇
  1975年   7篇
  1974年   5篇
  1973年   6篇
  1972年   4篇
排序方式: 共有802条查询结果,搜索用时 0 毫秒
91.
Dyspepsia is most optimally defined as pain or discomfort centred in the upper abdomen. The symptom complex may be caused by peptic ulcer disease, gastro-oesophageal reflux, or gastric cancer but is most often due to functional (or non-ulcer) dyspepsia. While upper endoscopy is the method of choice to determine the underlying cause of dyspepsia, it is expensive. A more pragmatic approach is needed in the Asia-Pacific region where health services are limited. A detailed treatment algorithm is given for managing patients presenting with new-onset dyspepsia and documented functional dyspepsia after endoscopy, and evidence to support this approach is reviewed. Prompt endoscopy is recommended for patients with alarm features. In patients without alarm features, treatment for 2–4 weeks with an empirical anti-secretory or prokinetic agent, followed by investigation using non-invasive Helicobacter pylori testing and treatment for patients who do not respond or relapse, is recommended. Trials of management strategies are now needed to establish the efficacy and cost-effectiveness of the approaches recommended.  相似文献   
92.
To test a method of obtaining specimens for microbiologic culture from the lower respiratory tract, we bronchoscoped 25 otherwise normal subjects with and without experimental rhinovirus infections and collected specimens for bacterial culture with a brush housed in a plugged double catheter apparatus. Fifty-two specimens of the lower respiratory tract were obtained from the 25 subjects; nasopharyngeal swabs were also obtained from each subject prior to bronchoscopy. Specimens obtained from the lower respiratory tract were positive for bacteria in 21 (84%) of 25 subjects and at 38 (73%) of 52 sites. The frequency of obtaining positive bacterial cultures was similar in volunteers with (69%) or without (90%) rhinovirus infection. Oropharyngeal contamination of bronchial specimens was minimized by administering atropine and by bronchoscoping subjects in the supine or Trendelenburg position. These data indicate that the plugged double catheter brush system does not consistently yield specimens that are free of bacterial contamination from the oropharynx.  相似文献   
93.

INTRODUCTION

The preliminary results of a pyrocarbon interpositional radiocarpal implant in a small cohort of patients were reviewed. As it is currently only a limited release product, we describe to potential users early complications and negative outcomes.

METHODS

Patients were assessed using pain levels, ranges of motion, grip strength, type of and time to return to work as well as pre-operative and post-operative DASH (Disabilities of the Arm, Shoulder and Hand) scores. Radiographs were taken and patient satisfaction was recorded.

RESULTS

All six patients were contacted. One was not satisfied. Three had reduced motion. None experienced squeaking. There were no immediate or late post-operative complications. There was one early volar displacement of an implant.

CONCLUSIONS

Although our early results are somewhat encouraging, further and longer studies are warranted before supporting the use of this particular pyrocarbon implant as a primary procedure.  相似文献   
94.
Little is known about the relationship between homeworking and mental health during the Covid-19 pandemic and how it might differ by keyworker status. To understand this relationship, we use longitudinal data collected over three time points during the pandemic from three British cohort studies born in 1958 (National Child Development Study), 1970 (British Cohort Study) and 1989–90 (Next Step) as well as from a population-based study stratified by four age groups (Understanding Society). We estimate the association between life satisfaction, anxiety, depression, and psychological distress and homeworking by key worker status using mixed effects models with maximum likelihood estimation to account for repeated measurements across the pandemic, allowing intercepts to vary across individuals after controlling for a set of covariates including pre-pandemic home working propensities and loneliness. Results show that key workers working from home showed the greatest decline in mental health outcomes relative to other groups. Pre-pandemic homeworking did not significantly change the nature of such a relationship and loneliness slightly attenuated some of the effects. Finally, mental health outcomes varied across age-groups and time points. The discussion emphasises the need to pay attention to key workers when assessing the relationship between mental health and homeworking.  相似文献   
95.
Bimodal stimulation, or stimulation of a cochlear implant (CI) together with a contralateral hearing aid (HA), can improve speech perception in noise However, this benefit is variable, and some individuals even experience interference with bimodal stimulation. One contributing factor to this variability may be differences in binaural spectral integration (BSI) due to abnormal auditory experience. CI programming introduces interaural pitch mismatches, in which the frequencies allocated to the electrodes (and contralateral HA) differ from the electrically stimulated cochlear frequencies. Previous studies have shown that some, but not all, CI users adapt pitch perception to reduce this mismatch. The purpose of this study was to determine whether broadened BSI may also reduce the perception of mismatch. Interaural pitch mismatches and dichotic pitch fusion ranges were measured in 21 bimodal CI users. Seventeen subjects with wide fusion ranges also conducted a task to pitch match various fused electrode–tone pairs. All subjects showed abnormally wide dichotic fusion frequency ranges of 1–4 octaves. The fusion range size was weakly correlated with the interaural pitch mismatch, suggesting a link between broad binaural pitch fusion and large interaural pitch mismatch. Dichotic pitch averaging was also observed, in which a new binaural pitch resulted from the fusion of the original monaural pitches, even when the pitches differed by as much as 3–4 octaves. These findings suggest that abnormal BSI, indicated by broadened fusion ranges and spectral averaging between ears, may account for speech perception interference and nonoptimal integration observed with bimodal compared with monaural hearing device use.  相似文献   
96.
97.
亚太地区炎症性肠病处理共识意见(一)   总被引:24,自引:0,他引:24  
虽然目前亚太地区尚无炎症性肠病(IBD)的大规模流行病学资料,但一系列研究显示其发病率和患病率呈上升趋势。与西方国家相比仍呈滞后现象。溃疡性结肠炎(UC)的发病率仍较克罗恩病(CD)高。除地域差异外。在一些多民族国家中,IBD尚可见种族差异。亚太地区IBD的遗传背景有异于西方国家。如据报道该地区CD患者未检出NOD2/CARDI5变异。一般而言,该地区IBD患者的临床过程似不如西方国家严重。 亚太地区IBD的诊断存在一些特殊问题。如缺乏IBD诊断金标准。存在多种小肠结肠炎,与IBD临床表现相似,使鉴别诊断特别困难。迄今为止,亚太地区IBD的诊断标准多采用西方国家的诊断标准。诊断必须逐步排除非IBD的小肠结肠炎。确诊应有典型的组织学表现。某些患者需借助随访和诊断性治疗才能确诊。进一步研究IBD发病机制将有助于开发更好的诊断标记物。 亚太地区IBD的治疗亦存在特殊问题。由于诊断困难。IBD患者常未能及时接受适当的药物治疗,但该地区仍广泛采用药物治疗方案。结合西方指南和本地经验可制定类似的处理原则。以利诱导缓解和维持缓解。提倡逐级使用基于病变范围、活动性和严重度的阶梯式治疗方案。对不同病例采用综合性、个体化的方法。随着对IBD发病机制和亚太地区IBD独特性的深入理解。合理、实用的药物治疗指南和应用生物制剂治疗将改善该地区IBD的治疗前景。  相似文献   
98.
99.
Juvenile retention polyps   总被引:2,自引:0,他引:2  
  相似文献   
100.
Surface shield: device to reduce personnel radiation exposure   总被引:2,自引:0,他引:2  
A simple device is described that can reduce personnel exposure from scatter radiation by up to 75%. The device consists of an oblong piece of shielding (0.75-mm lead equivalent) that is taped to the side of the patient during percutaneous renal stone removal and other interventional procedures. Contrary to other shields and barriers, this does not interfere with access to the patient. Scatter exposure data from phantom studies are presented and the rationale for surface shielding discussed.  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