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   2517篇
  免费   173篇
  国内免费   29篇
耳鼻咽喉   31篇
儿科学   73篇
妇产科学   3篇
基础医学   717篇
口腔科学   11篇
临床医学   71篇
内科学   262篇
皮肤病学   68篇
神经病学   12篇
特种医学   18篇
外科学   33篇
综合类   253篇
一般理论   1篇
预防医学   956篇
眼科学   12篇
药学   154篇
  1篇
中国医学   19篇
肿瘤学   24篇
  2023年   21篇
  2022年   24篇
  2021年   56篇
  2020年   58篇
  2019年   63篇
  2018年   71篇
  2017年   65篇
  2016年   79篇
  2015年   54篇
  2014年   114篇
  2013年   151篇
  2012年   112篇
  2011年   112篇
  2010年   65篇
  2009年   77篇
  2008年   93篇
  2007年   106篇
  2006年   98篇
  2005年   101篇
  2004年   93篇
  2003年   64篇
  2002年   109篇
  2001年   73篇
  2000年   64篇
  1999年   81篇
  1998年   61篇
  1997年   67篇
  1996年   64篇
  1995年   71篇
  1994年   58篇
  1993年   63篇
  1992年   41篇
  1991年   61篇
  1990年   53篇
  1989年   32篇
  1988年   29篇
  1987年   26篇
  1986年   17篇
  1985年   13篇
  1984年   12篇
  1983年   10篇
  1982年   7篇
  1981年   7篇
  1980年   5篇
  1979年   9篇
  1978年   2篇
  1976年   3篇
  1971年   2篇
  1970年   2篇
排序方式: 共有2719条查询结果,搜索用时 15 毫秒
1.
The performance of enzyme linked immunosorbent assays (EAST) for identifying six indoor allergens was evaluated using skin prick test (SPT) as reference tests in 154 children with allergic rhinitis. Sensitivity of EAST ranged from 9% (cat) to 54% (HDM) with specificity of 74%(cockroach) to 100% (cat) with an agreement ranged from 58 to 86%. Cut off values ?> ?0.35 kU/L showed best sensitivity and specificity. Our findings agree with extant literature which suggests that the ability of EAST to determine the precipitating allergen is moderate. Assays for definitively identifying the inhalant allergen are currently not available.  相似文献   
2.
目的 探讨石家庄市居民慢性阻塞性肺疾病检出情况及影响因素。方法 2021年9—12月采用整群随机抽样方法抽取石家庄市3个社区,对抽中社区的所有居民进行问卷调查和肺功能检查。利用描述流行病学方法分析社区人群慢性阻塞性肺疾病患病现状。应用单、多因素方法分析影响慢性阻塞性肺疾病发生的危险因素。结果 共2 348名居民完成问卷调查和肺功能检查,其中男1 205人,占51.32%,女1 143人,占48.68%,年龄31~76岁。共有146例检出慢性阻塞性肺疾病,检出率为6.22%,其中轻度69例,占47.26%,中度54例,占36.99%,重度23例,占15.75%,未检出极重度者。检出来的症状分布中,以咳嗽及咳痰的比例较高,分别为52.05%(76例)和49.32%(72例)。多因素Logistic回归分析结果显示年龄≥40岁(OR=1.705、1.936)、男性(OR=3.404)、居住在农村(OR=2.469)、偶尔或经常吸烟(OR=1.592、1.800)、有职业粉尘接触史(OR=2.179)、有哮喘家族史(OR=3.164)、有慢性阻塞性肺疾病家族史(OR=5.170)、有呼吸道反复感染史(OR=3.414)是石家庄市居民慢性阻塞性肺病患病的影响因素。结论 石家庄市居民的慢性阻塞性肺疾病患病情况不容乐观,且危险因素众多。重点针对中老年、吸烟、农村、有各种相关家族史的男性高危人群开展早期筛查和采取针对性干预措施,有助于对居民慢性阻塞性肺疾病进行防控。  相似文献   
3.
BackgroundDengue fever (DF) is the most rapidly spreading mosquito-borne viral disease. Practical vaccines or specific therapeutics are still expected. Environmental factors and genetic factors affect the susceptibility of Dengue virus (DV) infection. Asthma is a common allergic disease, with house dust mites (HDMs) being the most important allergens. Asthmatic patients are susceptible to several microorganism infections.MethodsA nationwide population-based cohort analysis was designed to assess whether to determine whether asthma can be a risk factor for DF.ResultsUnexpectedly, our data from a nationwide population-based cohort revealed asthmatic patients are at a decreased risk of DF. Compared to patients without asthma, the hazard ratio (HR) for DF in patients with asthma was 0.166 (95% CI: 0.118–0.233) after adjustment for possible confounding factors. In the age stratification, the adjusted HR for DF in young adult patients with asthma was 0.063. Dendritic cell-specific intercellular adhesion molecule 3-grabbing non-integrin (DC-SIGN) of dendritic cells (DCs) is an important entry for DV. Through another in vitro experiment, we found that HDM can diminish surface expression of DC-SIGN in monocyte-derived DCs and further decrease the cellular entry of DV.ConclusionsDecreased DC-SIGN expression in DCs of allergic asthmatic patient may be one of many factors for them to be protected against DF. This could implicate the potential for DC-SIGN modulation as a candidate target for designing therapeutic strategies for DF.  相似文献   
4.
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   
5.
The interest of the construction industry in alkali-activated materials has increased to the extent that these materials are recognized as alternatives to ordinary Portland cement-based materials in the quest for sustainable construction. This article presents the design and construction of a prototype of an eco-friendly house built from concrete blocks produced using alkali activation technology or geopolymerization. The prototype meets the requirements of the current Colombian Regulations for Earthquake Resistant Buildings (NSR-10) and includes standards related to the performance of the materials, design, and construction method for earthquake-resistant confined masonry of one- or two-story buildings. The alkali-activated blocks were obtained from different precursors (aluminosilicates), including a natural volcanic pozzolan, ground granulated blast furnace slag, fly ash, construction and demolition waste (concrete, ceramic, brick, and mortar), and red clay brick waste. The physical-mechanical characterization of the alkali-activated blocks allowed their classification according to the structural specifications of the Colombian Technical Standard NTC 4026 (equivalent to ASTM C90). The global warming potential (GWP) or “carbon footprint” attributed to the raw materials of alkali-activated blocks was lower (25.4–54.7%) than that of the reference blocks (ordinary Portland cement concrete blocks). These results demonstrate the potential of alkali-activated materials for application in the construction of eco-friendly houses.  相似文献   
6.
目的:评价安脱达尘螨变应原疫苗治疗过敏性哮喘的疗效及安全性。方法:采用自身对照方法,对125例尘螨过敏性哮喘患儿皮下注射特异性免疫疫苗(安脱达),记录治疗前后哮喘症状、合并用药评分,同时计算与免疫相关不良反应发生率,评价其安全性。结果:脱敏治疗1年后125例患儿哮喘症状明显改善,合并用药计分明显减少。80.0%(100/125)的哮喘患儿伴发过敏性鼻炎,脱敏治疗1年后鼻炎症状明显改善。23.2%的患儿因哮喘症状明显好转,在治疗第26周末自行停用合并药物,第52周末随访病情,哮喘复发率为10.3%(3/29)。125例患儿总计接受免疫治疗注射2676次,43例患儿出现100例次局部不良反应,局部不良反应的发生率为3.7%(100/2676),14例患儿出现23例次全身不良反应,全身不良反应发生率0.9%(23/2676),未出现致死性全身不良反应。结论:标准化变应原进行脱敏治疗在规范化操作下是一种安全有效的治疗方法。  相似文献   
7.
8.

Background

Aggression against doctors involved in after-hours house calls (AHHC) is widely perceived to be high. It is, however, unclear how doctors who perform this service manage the risk of aggressive patients during home visits.

Aims

The aim of this paper is to explore if and how doctors manage the risk of violence against them during AHHC.

Methods

A survey was designed and administered to all 300 Australian-based doctors engaged in AHHC under the National Home Doctor Service (NHDS). The survey was conducted from September 2014 to November 2014.

Results

There were 172 responses (57.3 per cent). Only 43 per cent of respondents adopted personal protective measures. The remaining 57 per cent had none; of those 6 per cent had never considered protective measures, and 31.8 per cent were aware of the risk of violence, but were unsure of what to do. Measures adopted include the use of chaperones/security personnel (34.1 per cent), dependence on surgery policies (31.2 per cent), de-escalation techniques (15.2 per cent), panic buttons (7.2 per cent), personal alarms (6.1 per cent), and others (6.5 per cent). Females were more likely to adopt personal protective measures than males (OR 4.94; p<0.01; CI 1.70–14.34), and Australian-trained doctors were less likely to do so relative to overseas-trained doctors (OR 0.35; p=0.04; CI 0.12–0.99).

Conclusion

Just over half of the doctors involved in AHHC took no precautions against aggressive attacks while on duty, and nearly one-third relied on the policies of their employing surgeries.  相似文献   
9.
The costimulatory receptor OX40 is expressed on activated T cells and regulates T‐cell responses. Here, we show the efficacy and mechanism of action of an OX40 blocking antibody using the chronic house dust mite (HDM) mouse model of lung inflammation and in vitro HDM stimulation of cells from HDM allergic human donors. We have demonstrated that OX40 blockade leads to a reduction in the number of eosinophils and neutrophils in the lavage fluid and lung tissue of HDM sensitized mice. This was accompanied by a decrease in activated and memory CD4+ T cells in the lungs and further analysis revealed that both the Th2 and Th17 populations were inhibited. Improved lung function and decreased HDM‐specific antibody responses were also noted. Significantly, efficacy was observed even when anti‐OX40 treatment was delayed until after inflammation was established. OX40 blockade also inhibited the release of the Th2 cytokines IL‐5 and IL‐13 from cells isolated from HDM allergic human donors. Altogether, our data provide evidence of a role of the OX40/OX40L pathway in ongoing allergic lung inflammation and support clinical studies of a blocking OX40 antibody in Th2 high severe asthma patients.  相似文献   
10.
Workers in a print shop are exposed to photocopier toner dust and paper dust over a prolonged period of time. However, there are only rare case reports of toner and paper dust induced lung damage in humans. We reviewed our consultation files for a period of 30 years from 1987 to 2018 to look for cases with a diagnosis of giant cell interstitial pneumonia (GIP), printer toner exposure and paper dust exposure resulting in lung disease. There were two cases which met our inclusion criteria. Slides, clinical histories and imaging were reviewed. Both the patients had worked in print shops, and had no history of exposure to hard metals. Patient 1 presented with shortness of breath and cough over several months, while patient 2 was asymptomatic at presentation. Both the patients underwent surgical lung biopsies. Histopathologic examination from both the cases showed a spectrum of pathology, including features of GIP, desquamative interstitial pneumonia, chronic bronchiolitis with lymphoid hyperplasia, and particulate matter consistent with toner. Energy dispersive spectroscopy was performed on one case, and it revealed no cobalt or tungsten particles. The unusual combination of findings is very suggestive that toner particles with or without paper dust exposure were responsible for the pathologic changes in the lungs of these patients. This possibility should be explored further with additional patients who work in print shops where they are exposed to paper dust and paper toner and have signs or symptoms of diffuse lung disease.  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