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   449篇
  免费   34篇
  国内免费   2篇
耳鼻咽喉   7篇
儿科学   16篇
妇产科学   11篇
基础医学   29篇
口腔科学   7篇
临床医学   79篇
内科学   70篇
皮肤病学   3篇
神经病学   15篇
特种医学   9篇
外科学   33篇
综合类   26篇
预防医学   115篇
眼科学   10篇
药学   38篇
中国医学   3篇
肿瘤学   14篇
  2024年   2篇
  2023年   17篇
  2022年   53篇
  2021年   47篇
  2020年   51篇
  2019年   56篇
  2018年   35篇
  2017年   16篇
  2016年   13篇
  2015年   12篇
  2014年   32篇
  2013年   28篇
  2012年   8篇
  2011年   25篇
  2010年   7篇
  2009年   10篇
  2008年   11篇
  2007年   9篇
  2006年   9篇
  2005年   19篇
  2004年   5篇
  2003年   4篇
  2002年   4篇
  2001年   3篇
  2000年   1篇
  1999年   1篇
  1996年   1篇
  1995年   1篇
  1990年   2篇
  1988年   1篇
  1986年   1篇
  1985年   1篇
排序方式: 共有485条查询结果,搜索用时 328 毫秒
11.
ObjectiveThere have been concerns about impacts of various aspects of taking part in research studies for a century. The concerns have not, however, been sufficiently well conceptualized to form traditions of study capable of defining and elaborating the nature of these problems. In this article we present a new way of thinking about a set of issues attracting long-standing attention.Study Design and SettingWe briefly review existing concepts and empirical work on well-known biases in surveys and cohort studies and propose that they are connected.ResultsWe offer the construct of “research participation effects” (RPE) as a vehicle for advancing multi-disciplinary understanding of biases. Empirical studies are needed to identify conditions in which RPE may be sufficiently large to warrant modifications of study design, analytic methods, or interpretation. We consider the value of adopting a more participant-centred view of the research process as a way of thinking about these issues, which may also have benefits in relation to research methodology more broadly.ConclusionResearchers may too readily overlook the extent to which research studies are unusual contexts, and that people may react in unexpected ways to what we invite them to do, introducing a range of biases.  相似文献   
12.
13.
《Substance use & misuse》2013,48(8-10):1229-1251
Trend analyses of the U.S. monitoring data systems (the National Household Survey on Drug Abuse and the Monitoring the Future Study) and of the country's surveillance program, the Community Epidemiology Work Group (CEWG), indicate that several new “drug abuse” patterns have emerged over the past several years. For adolescents, drug use rates are converging for females and males, the mean age at which youngsters initiate drug use has declined, and more young adolescents are reporting using drugs. Furthermore, emergent new drug use patterns are being observed by the CEWG. The use of drugs such as Rohypnol, the injecting of crack-cocaine, and the spread of methamphetamines by new traffickers challenge our existing knowledge and understanding of drug use and its prevention. The National Institute on Drug Abuse has funded several large longitudinal studies that follow selected children and adolescents into their twenties, and some into their thirties. This research has been a rich source of information on the determinants of initiating and continuing drug abuse. Yet the findings from the surveys have not been well explored by the longitudinal studies, nor have the findings from the longitudinal studies been used in the surveys to better understand the observed changing trends in drug use patterns. This paper addresses six issues that have been observed from the findings from analyses of data from the surveys or macro-epidemiologic studies. Information from the sub-population or micro-epidemiologic studies are reviewed for possible hypotheses to explain each issue. Suggestions for further research and implications for prevention also are presented.  相似文献   
14.
15.
16.
陕西省大骨节病病情现状与相关因素调查   总被引:3,自引:0,他引:3  
目的 进一步掌握陕西省大骨节病病情消长态势和相关环境因素对大骨节病发生、发展的影响,为今后大骨节病的防治决策提供依据.方法 在陕西省大骨节病病区范围内分别选择了6个项目调查点和20个省级自设监测点.临床检查7~12岁儿童2568例,右手X线拍片1788例.采集项目点粮样600份和发样300份,测定粮硒、发硒及食粮(180份)T-2毒素水平,调查相关因素与病情的关系.结果 全省23个病区县(区)26个调查点中,大骨节病临床Ⅰ度以上患者无检出,X线总检出率为1.29%;儿童发硒为(0.37±0.07)mg/kg,粮食硒(0.049±0.016)mg/kg,粮食T-2毒素(3.82±4.38)μg/kg.结论 陕西省儿童大骨节病病情处于基本控制后的平稳低发态势,病区内外环境硒水平的明显升高、饮食结构的明显改善、粮食卫生学质量的提高及经济收入的增加是病情得到控制的主要因素,应进一步深化防治措施落实和加强病区群众健康教育.  相似文献   
17.
ObjectiveThough the operating microscope (OM) has been the standard optical system in neurosurgery, a new technology called three-dimensional (3D) exoscope has emerged as an alternative. Herein, two types of 3D exoscopes for brain tumor surgery are presented. In addition, the advantages and limitations compared with the OM are discussed. MethodsIn the present study, 3D exoscope VOMS-100 or VITOM 3D was used in 11 patients with brain tumor who underwent surgical resection; the Kinevo 900 OM was used only in emergency. After completion of all surgeries, the participants were surveyed with a questionnaire regarding video image quality on the display monitor, handling of equipment, ergonomics, educational usefulness, 3D glasses, and expectation as a substitute for the OM. ResultsAmong 11 patients, nine patients underwent neurosurgical resection with only 3D exoscope; however, two patients required additional aid with the OM due to difficulty in hemostasis. Regarding video image quality, VITOM 3D was mostly equivalent to the OM, but VOMS-100 was not. However, both 3D exoscopes showed advantages in accessibility of instruments in the surgical field and occupied less space in the operating theater. Differences in ergonomics and educational usefulness between the exoscopes were not reported. Respondents did not experience discomfort in wearing 3D glasses and thought the exoscopes could be currently, and in the future, used as a substitute for the OM. ConclusionAlthough many neurosurgeons are not familiar with 3D exoscopes, they have advantages compared with the OM and similar image quality. Exoscopes could be a substitute for OM in the future if some limitations are overcome.  相似文献   
18.
《Journal of Evidence》2020,20(3):101459
ObjectiveThe dimensions of oral health–related quality of life (OHRQoL) Oral Function, Orofacial Pain, Orofacial Appearance, and Psychosocial Impact are the major areas where patients are impacted by oral diseases and dental interventions. The aim of this study was to evaluate whether dental patients' reasons to visit the dentist fit the 4 OHRQoL dimensions.MethodsDentists (N = 1580) from 32 countries participated in a web-based survey. For their patients with current oral health problems, dentists were asked whether these problems were related to teeth, mouth, and jaws' function, pain, appearance, or psychosocial impact or whether they do not fit the aforementioned 4 categories. Dentists were also asked about their patients who intended to prevent future oral health problems. For both patient groups, the proportions of oral health problems falling into the 4 OHRQoL dimensions were calculated.ResultsFor every 100 dental patients with current oral health problems, 96 had problems related to teeth, mouth, and jaws' function, pain, appearance, or psychosocial impact. For every 100 dental patients who wanted to prevent future oral health problems, 92 wanted to prevent problems related to these 4 OHRQoL dimensions. Both numbers increased to at least 98 of 100 patients when experts analyzed dentists' explanations of why some oral health problems would not fit the four dimension. For the remaining 2 of 100 patients, none of the dentist-provided explanations suggested evidence against the OHRQoL dimensions as the concepts that capture dental patients' suffering.ConclusionOral Function, Orofacial Pain, Orofacial Appearance, and Psychosocial Impact capture dental patients' oral health problems worldwide. These 4 OHRQoL dimensions offer a psychometrically sound and practical framework for patient care and research, identifying what is important to dental patients.  相似文献   
19.
BackgroundThe Obstetric Anaesthetists’ Association (OAA) has facilitated national surveys in obstetric anaesthesia since 1998. We wanted to examine trends in OAA-approved surveys since this time.MethodsOAA-approved surveys performed between January 1998 and December 2012 were examined for the year they were carried out, the format (postal or electronic), the target group and the response rate. We determined whether each survey was presented or published. For each survey published as a substantive paper, we identified the number of times the publication had been cited. We also surveyed lead obstetric anaesthetists and expert witnesses practising in obstetric anaesthesia on the perceived usefulness of OAA-approved surveys.ResultsOne hundred and thirty-five surveys approved by the OAA were carried out between 1998 and 2012. Response rates have fallen over the years, reaching a current plateau of 65%. Response rates varied with the target group. Seventy-eight percent of surveys were presented and 83% were published in some form. For surveys published as substantive papers (n=34, 25%), the median [IQR (range)] number of citations was 6 [3–11 (0–36)] per publication. Our survey of lead obstetric anaesthetists had a response rate of 62%. Those who replied rated OAA surveys a median [IQR (range)] of 6 [5–7 (1–9)] on a 0–10 scale of usefulness to their clinical practice.ConclusionsResponse rates to OAA-approved surveys have declined but remain acceptable despite an increase in the number of surveys performed. Most surveys were presented or published in some form.  相似文献   
20.
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