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Literature Search. in Evidence-biased Medicine. ผศ.นพ. อนิรุธ ภัทรากาญจน์. Aims of Literature Search. To solve clinical problems (EBM) To search for existing knowledge in order to conduct a research To update knowledge. “5A” of Evidence-Based Practice. ASSESS problem. ASK
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Literature Search in Evidence-biased Medicine ผศ.นพ. อนิรุธ ภัทรากาญจน์
Aims of Literature Search • To solve clinical problems (EBM) • To search for existing knowledge in order toconduct a research • To update knowledge
“5A” of Evidence-Based Practice ASSESS problem ASK the right question Professional experience Pathophysiology Pharmacology Psychology Organizational issues Costs Politics etc ACQUIRE search for the best available evidence APPRAISE the evidence ASSESS Decision making APPLY
General Search Strategy Search the best available database Define relevant, searchable terms Design search strategy No Relevant results? Yes Summarize & Appraise the evidence Poor GOOD Apply the evidence
Well-built Clinical Question : PICO • P Patients or population • I Intervention • C Comparison • OOutcome • Type of question • Therapy, etiology, prognosis, diagnosis, etc. • Study design • Descriptive, case-control, RCT, etc.
Example อยากทราบว่าในผู้ป่วยเด็กที่เป็น diabetic nephropathy จะมีอัตราการเกิด ESRD ต่างกันหรือไม่ ระหว่างกลุ่มที่ได้รับ ACEI ร่วมกับ ARB เปรียบเทียบกับกลุ่มที่ได้รับ ACEI เพียงอย่างเดียว
Formulate the question • Patients : children with diabetic nephropathy • Intervention : ACEI+ARB • Comparison : ACEI • Outcome : ESRD • Question : therapy • Design : systematic review, RCT
Tools • Hardware • A computer with (good & fast) online access • LAN, MODEM (ADSL, cable) • Software • Web browser • Internet Explorer, FireFox, Opera • Adobe Reader® (latest version from adobe.com) • Reference management softwares • EndNote®, ProCite®, Reference Manager® • Electronic databases • On-line • Off-li
Expert Standard textbooks Teaching documents Meeting presentation Proceedings of presentation Thesis Current contents References References of the references Index books Science citation index Index medicus (1879) Excerpta medica (1948) Electronic databases Medical Clinical Evidence Sources
Search Exhaustively • Electronic databases • Printed journals, hand-search • Unpublished articles • Expert seeking • Pharmaceutical companies data • Grey literature • General internet search engines: google, yahoo, msn, altavista, itools
General - Google - Yahoo - MSN - Live - Altavista - Excite - HotBot - Lycos - Go.com - Ask.com Special search engine - Clusty.com - Kartoo.net Metasearch engines - Gahooyoogle.com (search Yahoo, Google,all at once) - Arrowsearch.net - Copernic Agent Internet Search Engines
Electronic Databases • Bibliographic databases Medline Embase Scopus Science Citation Index LILACS Open access databases Grey literature databases • Web search engines Google Scholar Scirus
Bibliographic Database • Medline • About 5,000 journals • Free access via PubMed • http://www.ncbi.nlm.nih.gov/pubmed/ • Now include “Oldmedline” • Oldest article in 1865 Trans Am Ophthalmol Soc • PubMed Central (http://www.ncbi.nlm.nih.gov/pmc/) • Free full-text • Mostly articles in English from North American region
Bibliographic Databases (Thai) • Siriraj: Thai Medical Index (http://www.medlib.si.mahidol.ac.th/) • Chula: Thai Index Medicus (http://www.library.md.chula.ac.th/) • Other Thai databases • ศูนย์บริการความรู้ทางวิทยาศาสตร์และเทคโนโลยี(http://www.stks.or.th/web/) • ห้องสมุดงานวิจัย สำนักงานคณะกรรมการวิจัยแห่งชาติ (http://www.riclib.nrct.go.th/)
Bibliographic Databases (Thai) • Thai journal pointer • Journal Link (www.journallink.or.th) • Thai journal citation index center (TCI) (www.kmutt.ac.th/jif/public_html/)
Pre-filtered Clinical Resources • Cochrane library • Online access: http://www.thecochranelibrary.com/view/0/index.html • Offline access: CD updated quarterly • ACP Journal Club (previous Best Evidence) • www.acpjc.org • Clinical Evidence • www.clinicalevidence.com • Evidence-based Medicine (EBM Online) • http://ebm.bmj.com/
Pre-filtered Clinical Resources • UpToDate • www.uptodate.com • CD updated every 4 months
Multidisciplinary Clinical Resources • Ovid.com • MDConsult.com • Full-text of “Clinics of North America” Journals • Full-text of “Year Books” • Not all have pdf files
Electronic Text Books • Harrison Online • www.harrisonsonline.com • www.harrisonsmed.com (store)
What is PubMed? • A web-based retrieval system developed byNCBI (a part of Entrez retrieval system) • Free version of MEDLINE on the web NIH National Institutes of Health NLM National Library of Medicine National Center for Biotechnology Information NCBI
PubMed Database • A database of bibliographic information drawnprimarily from the life sciences literature • PubMed contains links to • Full-text articles at participating publishers' Websites • Other third party sites such as libraries andsequencing centers • All citations in MEDLINE are assigned MeSHTerms and Publication Types from NLM'scontrolled vocabulary.
What Does MEDLINE Cover? • Not only medicine • medicine • nursing • dentistry • veterinary medicine • health care system • preclinical sciences e.g., molecular biology
How Big is MEDLINE? • > 5,000 biomedical journals • > 16 million citations back to 1865 • Published in the U.S. and 70 other countries. • Coverage is worldwide, but most records are from English-language sources or have English abstracts • MEDLINE contains citations, not full-textarticles (PubMed provides links to full-text)
A basic search • Identify the key concepts for your search. Example: Find citations about bronchodilators for treating asthma in children. The key concepts are bronchodilators, asthma and children • Enter terms into the search box. • Press the Enter key or click Search.
Combining search terms with Boolean operators • AND retrieves results that include all the search terms. • OR retrieves results that include at least one of the search terms. • NOT excludes the retrieval of terms from your search.
Combining search terms with Boolean operators • Examples • Find citations on DNA that were authored by Dr. Crick in 1993: dna [mh] AND crick [au] AND 1993 [dp] • Find citations on the effects of heat or humidity on multiple sclerosis: (heat OR humidity) AND multiple sclerosis • Find citations about arthritis excluding the Publication Type Letter: arthritis NOT letter [pt]
Automatic term mapping (ATM) • Untagged terms that are entered in the search box are matched (in this order) against • MeSH (Medical Subject Headings) translation table • Journals translation table • Full Author translation table • Author index • Full Investigator (Collaborator) translation table • Investigator (Collaborator) index
Automatic term mapping (ATM) • To bypass ATM, using the following formats: • Enclose the phrase in double quotes: “kidney allograft” • Use a search tag: kidney allograft[tw] • Use a hyphen: first-line • Truncate: kidney allograft*
Truncating search terms • Example flavor* Finds terms that begin with the root term flavor, such as flavored, flavorful, flavoring, etc.
MeSH • NLM's controlled vocabulary thesaurus. • Terms naming descriptors in a hierarchical structure that permits searching at various levels of specificity.
Search Field Descriptions and Tags • Example • Search for articles about influenza published in the New England Journal of Medicine • influenza [mh] AND n engl j med [ta]
Searching by author • Enter the author’s name in the format of last name followed by initials. Omit punctuation. • Examples smith jajones k • If only the author's last name is entered, tag the name with the author search field [au] • Full author names may be searched for citations published from 2002
Searching by journal title • Enter in the search box one of the following: • full journal title (e.g., molecular biology of the cell) • title abbreviation (e.g., mol biol cell) • To find full journal names, use the Journals database • Use the Single Citation Matcher(http://www.ncbi.nlm.nih.gov/corehtml/query/static/citmatch.html)
Limits • by dates, type of article, languages, species, gender, subsets, ages, text options, and specific search fields. http://www.ncbi.nlm.nih.gov/pubmed/
Combining searches using History • Previous searches can be combined or used in subsequent searches http://www.ncbi.nlm.nih.gov/pubmed/
PubMed Results