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   2693篇
  免费   204篇
  国内免费   6篇
耳鼻咽喉   42篇
儿科学   116篇
妇产科学   78篇
基础医学   357篇
口腔科学   48篇
临床医学   209篇
内科学   671篇
皮肤病学   40篇
神经病学   188篇
特种医学   140篇
外科学   277篇
综合类   94篇
一般理论   1篇
预防医学   259篇
眼科学   41篇
药学   167篇
中国医学   8篇
肿瘤学   167篇
  2023年   12篇
  2022年   32篇
  2021年   56篇
  2020年   44篇
  2019年   58篇
  2018年   83篇
  2017年   48篇
  2016年   62篇
  2015年   72篇
  2014年   75篇
  2013年   80篇
  2012年   122篇
  2011年   154篇
  2010年   108篇
  2009年   86篇
  2008年   131篇
  2007年   124篇
  2006年   126篇
  2005年   131篇
  2004年   117篇
  2003年   113篇
  2002年   96篇
  2001年   87篇
  2000年   96篇
  1999年   86篇
  1998年   53篇
  1997年   41篇
  1996年   28篇
  1995年   33篇
  1994年   27篇
  1993年   28篇
  1992年   54篇
  1991年   34篇
  1990年   39篇
  1989年   46篇
  1988年   37篇
  1987年   45篇
  1986年   47篇
  1985年   26篇
  1984年   20篇
  1983年   21篇
  1982年   8篇
  1981年   9篇
  1980年   10篇
  1978年   7篇
  1977年   10篇
  1975年   13篇
  1974年   7篇
  1969年   6篇
  1967年   6篇
排序方式: 共有2903条查询结果,搜索用时 15 毫秒
91.
OBJECTIVE: To determine whether breath sound distribution maps can differentiate between patients with pneumonia or pleural effusion versus healthy controls. METHODS: We recorded breath sounds from 20 patients conventionally diagnosed as having pleural effusion, 20 patients conventionally diagnosed as having pneumonia, and 60 healthy controls, of whom 20 served as a learning sample. All subjects were examined with a computer-based multi-sensor breath sound mapping device that records, analyzes, and displays a dynamic map of breath sound distribution. The physicians who interpreted the breath sound images were first trained in identifying common characteristics of the images from the learning sample of normals. Then the images from the 40 patients and the 40 controls were interpreted as either normal or abnormal. RESULTS: In the normal images, the left and right lung images developed synchronously and had similar size, shape, and intensity. The sensitivity and specificity of blinded differentiation between normal and abnormal images when the physician interpreter did not know the patient's workup were 82.5% and 80%, respectively. The sensitivity and specificity of blinded detection of normal and abnormal images when the interpreter did know the patient' workup were 90% and 88%, respectively. CONCLUSIONS: Computerized dynamic imaging of breath sounds is a sensitive and specific tool for distinguishing pneumonia or pleural effusion from normal lungs. The role of computerized breath sound analysis for diagnosis and monitoring of lung diseases needs further evaluation.  相似文献   
92.
Die Ophthalmologie - Eine Raumforderung der Lider im jungen Erwachsenenalter ist oft ein Zeichen einer Entzündung, eines Traumas oder einer benignen Neoplasie. Ziel dieser Kasuistik ist es,...  相似文献   
93.
Chronic measles virus infection of the brain causes subacute sclerosing panencephalitis (SSPE), a progressive, relentless fatal disorder. We report a 52‐year‐old male who developed focal, chronic persistent measles virus infection of the brain following interferon and ribavirin therapy for hepatitis C, and who responded to steroid therapy. This case, diametrically different from SSPE, has 2 unique features, its focal nature and its permissive response to steroids, that may add to the understanding of the pathogenesis of SSPE and the mechanism enabling viruses to evade the immune response and establish persistent brain infection. Ann Neurol 2014;75:967–970  相似文献   
94.
95.
Introduction and objectivesAsian desert dust has recently been recognized as a trigger for acute myocardial infarction. The inflow of dust from the Sahara into Spain impairs air quality due to an increase in particulate matter concentrations in the ambient air. The aim of the present study was to elucidate whether Saharan dust events are associated with the incidence of acute coronary syndrome (ACS) in patients living near North Africa, the major global dust source.MethodsWe prospectively collected data on hospitalizations due to ACS in 2416 consecutive patients from a tertiary care hospital (Canary Islands, Spain) from December 2012 to December 2017. Concentrations of particulate matter with an aerodynamic diameter 10 microns or smaller (PM10) and reactive gases were measured in the European Air Quality Network implemented in the Canary Islands. We applied the time-stratified case crossover design using conditional Poisson regression models to estimate the impact of PM10 Saharan dust events on the incidence of ACS.ResultsThe occurrence of Saharan dust events observed 0 to 5 days before the onset of ACS was not significantly associated with the incidence of ACS. Incidence rate ratios (IRR) of PM10 levels 1, 2, 3, 4 and 5 days before ACS onset (for changes in 10 μg/m3) were 1.27 (95%CI, 0.87-1.85), 0.92 (95%CI, 0.84-1.01), 0.74 (95%CI, 0.45-1.22), 0.98 (95%CI, 0.87-1.11), and 0.95 (95%CI, 0.84-1.06), respectively.ConclusionsExposure to Saharan desert dust is unlikely to be associated with the incidence of ACS.  相似文献   
96.
OBJECTIVES: This randomized trial compared repeat stenting with balloon angioplasty (BA) in patients with in-stent restenosis (ISR). BACKGROUND: Stent restenosis constitutes a therapeutic challenge. Repeat coronary interventions are currently used in this setting, but the recurrence risk remains high. METHODS: We randomly assigned 450 patients with ISR to elective stent implantation (224 patients) or conventional BA (226 patients). Primary end point was recurrent restenosis rate at six months. Secondary end points included minimal lumen diameter (MLD), prespecified subgroup analyses, and a composite of major adverse events. RESULTS: Procedural success was similar in both groups, but in-hospital complications were more frequent in the balloon group. After the procedure MLD was larger in the stent group (2.77 +/- 0.4 vs. 2.25 +/- 0.5 mm, p < 0.001). At follow-up, MLD was larger after stenting when the in-lesion site was considered (1.69 +/- 0.8 vs. 1.54 +/- 0.7 mm, p = 0.046). However, the binary restenosis rate (38% stent group, 39% balloon group) was similar with the two strategies. One-year event-free survival (follow-up 100%) was also similar in both groups (77% stent vs. 71% balloon, p = 0.19). Nevertheless, in the prespecified subgroup of patients with large vessels (> or =3 mm) the restenosis rate (27% vs. 49%, p = 0.007) and the event-free survival (84% vs. 62%, p = 0.002) were better after repeat stenting. CONCLUSIONS: In patients with ISR, repeat coronary stenting provided better initial angiographic results but failed to improve restenosis rate and clinical outcome when compared with BA. However, in patients with large vessels coronary stenting improved the long-term clinical and angiographic outcome.  相似文献   
97.
98.
99.
Close to 6 million Americans have Alzheimer's disease (AD) or Alzheimer's disease and related dementia (AD/ADRD). These high-need, high-cost patients are vulnerable to receiving poor quality uncoordinated care, ultimately leading to adverse health outcomes, poor quality of life, and misuse of resources. Improving the care of persons living with dementia (PLWD) and their caregivers is an urgent public health challenge that must be informed by high-quality evidence. Although prior research has elucidated opportunities to improve AD/ADRD care, the adoption of promising interventions has been stymied by the lack of research evaluating their effectiveness when implemented under real-world conditions. Embedded pragmatic clinical trials (ePCTs) in healthcare systems have the potential to accelerate the translation of evidence-based interventions into clinical practice. Building from the foundation of the National Institutes of Healthcare Systems Collaboratory, in September 2019 the National Institute on Aging Imbedded Pragmatic AD/ADRD Clinical Trials (IMPACT) Collaboratory was launched. Its mission is to build the nation's capacity to conduct ePCTs within healthcare systems for PLWD and their caregivers by (1) developing and disseminating best practice research methods, (2) supporting the design and conduct of ePCTs including pilot studies, (3) building investigator capacity through training and knowledge generation, (4) catalyzing collaboration among stakeholders, and (5) ensuring the research includes culturally tailored interventions for people from diverse backgrounds. This report presents the rationale, structure, key activities, and markers of success for the overall NIA IMPACT Collaboratory. The articles that follow in this special Issue describe the specific work of its 10 core working groups and teams. J Am Geriatr Soc 68:S1–S7, 2020 .  相似文献   
100.
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