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   947篇
  免费   81篇
  国内免费   17篇
耳鼻咽喉   12篇
儿科学   30篇
妇产科学   22篇
基础医学   57篇
口腔科学   15篇
临床医学   168篇
内科学   219篇
皮肤病学   29篇
神经病学   40篇
特种医学   27篇
外科学   92篇
综合类   63篇
预防医学   87篇
眼科学   4篇
药学   84篇
  2篇
中国医学   17篇
肿瘤学   77篇
  2024年   3篇
  2023年   53篇
  2022年   93篇
  2021年   109篇
  2020年   81篇
  2019年   52篇
  2018年   66篇
  2017年   36篇
  2016年   34篇
  2015年   40篇
  2014年   96篇
  2013年   70篇
  2012年   57篇
  2011年   53篇
  2010年   30篇
  2009年   34篇
  2008年   17篇
  2007年   22篇
  2006年   41篇
  2005年   18篇
  2004年   17篇
  2003年   9篇
  2002年   5篇
  2001年   3篇
  2000年   1篇
  1999年   1篇
  1998年   1篇
  1996年   1篇
  1995年   1篇
  1987年   1篇
排序方式: 共有1045条查询结果,搜索用时 15 毫秒
11.
《Clinical microbiology and infection》2018,24(10):1101.e1-1101.e6
ObjectivesSeveral outbreaks of severe infections due to contamination of gastrointestinal (GI) endoscopes, mainly duodenoscopes, have been described. The rate of microbial endoscope contamination varies dramatically in literature. The aim of this multicentre prospective study was to evaluate the hygiene quality of endoscopes and automated endoscope reprocessors (AERs) in Tyrol/Austria.MethodsIn 2015 and 2016, a total of 463 GI endoscopes and 105 AERs from 29 endoscopy centres were analysed by a routine (R) and a combined routine and advanced (CRA) sampling procedure and investigated for microbial contamination by culture-based and molecular-based analyses.ResultsThe contamination rate of GI endoscopes was 1.3%–4.6% according to the national guideline, suggesting that 1.3–4.6 patients out of 100 could have had contacts with hygiene-relevant microorganisms through an endoscopic intervention. Comparison of R and CRA sampling showed 1.8% of R versus 4.6% of CRA failing the acceptance criteria in phase I and 1.3% of R versus 3.0% of CRA samples failing in phase II. The most commonly identified indicator organism was Pseudomonas spp., mainly Pseudomonas oleovorans. None of the tested viruses were detected in 40 samples. While AERs in phase I failed (n = 9, 17.6%) mainly due to technical faults, phase II revealed lapses (n = 6, 11.5%) only on account of microbial contamination of the last rinsing water, mainly with Pseudomonas spp.ConclusionsIn the present study the contamination rate of endoscopes was low compared with results from other European countries, possibly due to the high quality of endoscope reprocessing, drying and storage.  相似文献   
12.

Aim

The European Pressure Ulcer Advisory Panel, the Pan Pacific Pressure Injury Alliance, and the National Pressure Ulcer Advisory Panel are updating the ‘Prevention and Treatment of Pressure Ulcers: Clinical Practice Guideline’ (CPG) in 2019. The aim of this contribution is to summarize and to discuss the guideline development protocol for the 2019 update.

Methods

A guideline governance group determines and monitors all steps of the CPG development. An international survey of consumers will be undertaken to establish consumer needs and interests. Systematic evidence searches in relevant electronic databases cover the period from July 2013 through August 2018. Risk of bias of included studies will be assessed by two reviewers using established checklists and an overall strength of evidence assigned to the cumulative body of evidence. Small working groups review the evidence available for each topic, review and/or draft the guideline chapters and recommendations and/or good practice statements. Finally, strength of recommendation grades are assigned. The recommendations are rated based on their importance and their potential to improve individual patient outcomes using an international formal consensus process.

Discussion

Major methodological advantages of the current revision are a clear distinction between evidence-based recommendations and good practice statements and strong consumer involvement.

Conclusion

The 2019 guideline update builds on the previous 2014 version to ensure consistency and comparability. Methodology changes will improve the guideline quality to increase clarity and to enhance implementation and compliance. The full guideline development protocol can be accessed from the guideline website (http://www.internationalguideline.com/).  相似文献   
13.
All current guidelines use the 10-year risk of a cardiovascular event to select subjects for statin primary preventive therapy. Benefit from therapy is stated to be determined by risk with the result that statin primary preventive therapy is initiated only when the risk of a cardiovascular event over the next decade exceeds a specified level. Thus all current guidelines are based primarily on the Risk-Benefit paradigm of primary prevention. The recent American Heart Association/American College of Cardiology guidelines differ from others in basing selection for statin therapy virtually exclusively on risk except for those few subjects with markedly elevated levels of low-density lipoprotein cholesterol (LDL-C). The Causal Exposure paradigm differs from the Risk-Benefit paradigm in that the objective of therapy is to prevent the anatomic disease within arterial walls that produces cardiovascular risk. Moreover, the anatomic disease and, therefore, the cardiovascular risk, is a function of the injurious action of the causal factors of vascular disease, such as blood pressure and LDL, on the arterial wall over long periods. In this article, we explain the strengths and weaknesses of both paradigms to provide a more secure framework to compare the strengths and weaknesses in the different cholesterol guidelines with particular emphasis on the evidence that the cardiovascular risk and the benefit from statin therapy is related to the level of LDL.  相似文献   
14.
Guideline Summary

All substances are capable of producing toxicity, so nothing is completely non‐toxic. Minimally toxic substances are those which produce little toxicity, minor self‐limited toxicity, or clinically insignificant effects at most doses. Examples include silica gel, A&D ointment, chalk, lipstick, and non‐camphor lip balms, watercolors, hand dishwashing detergents, non‐salicylate antacids (excluding magnesium or sodium bicarbonate containing products), calamine lotion, clay, crayons, diaper rash creams and ointments, fabric softeners/sheets, glow products, glue (white, arts, and crafts type), household plant food, oral contraceptives, pen ink, pencils, starch/sizing, throat lozenges without local anesthetics, topical antibiotics, topical antifungals, topical steroids, topical steroids with antibiotics, and water‐based paints. Minimally toxic exposures have the following characteristics: (1) The information specialist has confidence in the accuracy of the history obtained and the ability to communicate effectively with the caller. (2) The information specialist has confidence in the identity of the product(s) or substance(s) and a reasonable estimation of the maximum amount involved in the exposure. (3) The risks of adverse reactions or expected effects are acceptable to both the information specialist and the caller based on available medical literature and clinical experience. (4) The exposure does not require a healthcare referral since the potential effects are benign and self‐limited. However, decisions regarding patient disposition should take into account the patient's intent, symptoms, and social environment. In addition, individual patient circumstances (e.g., pregnancy, pre‐existing medical conditions, therapeutic interventions) need to be considered. Minimally toxic exposures may vary in route (dermal, inhalation, ingestion, ocular), chronicity (acute, chronic), and substance composition (single or multi‐ingredient, single or multiple product). Future categorization of substances as “minimally toxic” should be based on a process involving review of current knowledge, a thorough analysis of poisoning experience, and prospective validation.  相似文献   
15.
16.
The purpose of this Special Communication is to summarize guidelines and recommendations stemming from an expert panel convened by the National Institutes of Health, National Center for Medical Rehabilitation Research (NCMRR) for a workshop entitled The Future of Medical Rehabilitation Clinical Trials, held September 29-30, 2016, at the NCMRR offices in Bethesda, Maryland. The ultimate goal of both the workshop and this summary is to offer guidance on clinical trials design and operations to the medical rehabilitation research community, with the intent of maximizing the effect of future trials.  相似文献   
17.
Data generated using standardized testing protocols for toxicity studies generally provide reproducible and reliable results for establishing safe levels and formulating risk assessments. The findings of three OECD guideline-type oral toxicity studies of different duration in rats are summarized in this publication; each study evaluated different titanium dioxide (TiO2) particles of varying sizes and surface coatings. Moreover, each study finding demonstrated an absence of any TiO2 -related hazards. To briefly summarize the findings: 1) In a subchronic 90-day study (OECD TG 408), groups of young adult male and female rats were dosed with rutile-type, surface-coated pigment-grade TiO2 test particles (d50 = 145 nm − 21% nanoparticles by particle number criteria) by oral gavage for 90 days. The no-adverse-effect level (NOAEL) for both male and female rats in this study was 1000 mg/kg bw/day, the highest dose tested. The NOAEL was determined based on a lack of TiO2 particle-related adverse effects on any in-life, clinical pathology, or anatomic/microscopic pathology parameters; 2) In a 28-day repeated-dose oral toxicity study (OECD TG 407), groups of young adult male rats were administered daily doses of two rutile-type, uncoated, pigment-grade TiO2 test particles (d50 = 173 nm by number) by daily oral gavage at a dose of 24,000 mg/kg bw/day. There were no adverse effects measured during or following the end of the exposure period; and the NOAEL was determined to be 24,000 mg/kg bw/day; 3) In an acute oral toxicity study (OECD TG 425), female rats were administered a single oral exposure of surface-treated rutile/anatase nanoscale TiO2 particles (d50 = 73 nm by number) with doses up to 5000 mg/kg and evaluated over a 14-day post-exposure period. Under the conditions of this study, the oral LD50 for the test substance was >5000 mg/kg bw. In summary, the results from these three toxicity studies – each with different TiO2 particulate-types, demonstrated an absence of adverse toxicological effects. Apart from reporting the findings of these three studies, this publication also focuses on additional critical issues associated with particle and nanotoxicology studies. First, describing the detailed methodology requirements and rigor upon which the standardized OECD 408 guideline subchronic oral toxicity studies are conducted. Moreover, an attempt is made to reconcile the complex issue of particle size distribution as it relates to measurements of nanoscale and pigment-grade TiO2 particles. Clearly this has been a confusing issue and often misrepresented in the media and the scientific literature. It is clear that the particle-size distribution for pigment-grade TiO2, contains a small (“tail”) component of nanoscale particles (i.e., 21% by particle number and <1% by weight in the test material used in the 90-day study). However, this robust particle characterization finding should not be confused with mislabeling the test materials as exclusively in the nanoscale range. Moreover, based upon the findings presented herein, there appears to be no significant oral toxicity impact contributed by the nanoscale component of the TiO2 Test Material sample in the 90-day study. Finally, it seems reasonable to conclude that the study findings should be considered for read-across purposes to food-grade TiO2 particles (e.g., E171), as the physicochemical characteristics are quite similar.  相似文献   
18.
19.
2015年我国第一个原发性硬化性胆管炎(PSC)的专家共识颁布。近年来PSC的临床研究提供了PSC新的研究数据和资料。为此,中华医学会肝病学分会自身免疫性肝病学组组织专家组对近年来的文献证据进行了评估,制定了本指南。本指南共有PSC推荐意见21条。为了利于鉴别PSC和IgG4相关硬化性胆管炎(IgG4-SC),也附有IgG4-SC的10条推荐意见。本指南的目的是为临床PSC和IgG4-SC的诊治提供参考和指导。  相似文献   
20.
Hepatocellular carcinoma (HCC) is the most common type of primary liver cancer. Several treatment options are available for managing HCC patients, classified roughly as local, local-regional, and systemic therapies. The high post-monotherapy recurrence rate of HCC urges the need for the use of combined modalities to increase tumor control and patient survival. Different international guidelines offer treatment recommendations based on different points of view and classification systems. Radiotherapy (RT) is a well-known local-regional treatment modality for managing many types of cancers, including HCC. However, only some of these treatment guidelines include RT, and the role of combined modalities is rarely mentioned. Hence, the present study reviewed clinical evidence for the use of different combined modalities in managing HCC, focusing on modern RT's role. Modern RT has an increased utility in managing HCC patients, mainly due to two driving forces. First, technological advancement (e.g., stereotactic body radiotherapy and advanced proton-beam therapy) enables precise delivery of radiation to increase tumor control and reduce side effects in the surrounding normal tissue. Second, the boom in developing target therapies and checkpoint-blockade immunotherapy prolongs overall survival in HCC patients, re-emphasizing the importance of local tumor control. Remarkably, RT combines with systemic therapies to generate the systemic therapy augmented by radiotherapy effect, a benefit now being actively investigated.  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