literature searching - med.mahidol.ac.th · literature searching •needed for every study before...
TRANSCRIPT
Literature Searching
Pawin Numthavaj M.D.
Section for Clinical Epidemiology and Biostatistics
Faculty of Medicine, Ramathibodi Hospital, Mahidol University
Bangkok, Thailand
www.ceb-rama.org
Literature searching
•Needed for every study before study conduction
•Provide the knowledge of “Gap of information”
•Why should you do your research
•Conducting a systematic review recommended
Study Identification Process
Select Database(s) to Use
Develop Search Strategy
Searching
Explore Results from Searching
Export into Reference Manager
ModifySearch Strategy
DatabaseJournal Articles Databases
• MEDLINE
• EMBASE
• SCOPUS
• Cochrane databases
• DARE (Database of Abstracts of Reviews of Effects)
• Web of Science
• CINAHL
• PsycINFO
• Etc.
Grey Literature
• Organization reports
• Governmental reports
• Conference Proceedings
• Dissertation & Theses
• Web
Multiple Databases
MEDLINE
EMBASECINAHL
Research Question
•P Patient
• I Intervention
•C Comparison
•O Outcome
PBell Palsy
Idiopathic Facial Palsy
I
Antiviral
Acyclovir
Valacyclovir
Steroid
Prednisolone
Methylprednisolone
C Steroid
Prednisolone
Methylprednisolone
O
Recovery Rate
House-Brackmann Scale
Sunnybrook Scale
AND
AND
AND
Group Your Question into Terms
•Terms #1 Antiviral• Subject Headings “Antiviral agents”• Text words “Antivirus”, “Antiviral drug”, …
•Terms #2 Steroid• Subject Headings “Steroids”• Text words “Steroid”, “Prednisolone”, …
•Terms #3 Bell Palsy• Subject Headings “Bell Palsy”
• Text words “Bell Palsy”, “Idiopathic facialparalysis”, …
Combination of Search Terms
•Use “AND” between domains (P/I/C/O)
•Use “OR” inside domains for similar terms or terms that have several synonyms
•Try to use “keyword searching”
Subject Headings
Database Subject Headings
MEDLINE MeSH
EMBASE EMTREE
CINAHL CINAHL Headings
Cochrane Library MESH
PsycINFO Thesaurus of Psychological Index Terms
SCOPUS N/A
Web of Science N/A
Search Engine and Database
Search Engine Database(s)
PubMed MEDLINE
Ovid MEDLINE, EMBASE, …
Scopus SCOPUS
PubMed Searching
PubMed
•Free search engine
•Comprises of MEDLINE database
•Maintain by US National Library of Medicine, National Institutes of Health
•First released in 1996
•Accessed from “http://www.pubmed.gov”
MEDLINE
•1946 to present material
•5,600 journals in 39 languages
•2,000 - 4,000 references added each day
•Biomedicine and health
Frequently Used Functions in PubMed
1. MESH
2. Search Operators
3. Limits
4. Clipboard
5. Save searches
6. Advanced search
7. Citation matcher
8. Clinical Queries
9. Retrieval of full text paper
MESH
•Medical Subject Heading
•Keyword system in Medline
Search Operators
•Truncated search term (wildcards)• flavor* = flavoring + flavored + flavors• synerchi* = synerchiae + synerchia
•Combining search terms• AND• OR• NOT• ( )
Limits
•Filter unwanted results• Age: infants, adults, …• Article types: original
studies, RCTs, Meta-analysis, …
• Article language
• Human/animal• Recently published
Clipboard
•Stored items for later review
•Max 500 items
•8 hours before deleted
•Send to ‘collection’ instead if you want to permanently stored
• (Need My NCBI account)
Saved search
•Save for later updates
•Useful when you’re doing systematic review
•Can also automatically e-mail updates
Advanced Search
•Search in command line-based
•Useful for complex searches
•Use # for referring to previous searches
•Operators: AND, OR, NOT, and ()
Download History
•CSV File
•Open in Spreadsheet programs (Excel)
•For use in report of search strategy supplementary table
Export to EndNote
Export to EndNote
•Send To command
•File• Choose MEDLINE• In EndNote choose
PubMed (NLM)
•Citation manager• .nbib EndNote• Limit 200 article
maximum
Citation Matcher
• Locate an article when you know the author name / title / journal name / volume / pages
•http://www.ncbi.nlm.nih.gov/pubmed/citmatchor visit pubmed.gov and look for Single Citation Matcher
Example
•Try to find this article from PubMed
•REFERENCE: "Itch Relief by Mirror Scratching. A Psychophysical Study," Christoph Helmchen, Carina Palzer, Thomas F. Münte, Silke Anders, Andreas Sprenger, PLoS ONE, vol. 8, no 12, December 26, 2013, e82756.
Clinical Queries
• “Filter” for specific area of question
•Etiology•Diagnosis•Therapy•Prognosis•Clinical Prediction
Guides•Systematic Review
Category Optimized ForSensitive/
SpecificPubMed Equivalent
therapysensitive/broad 99%/70%
((clinical[Title/Abstract] AND trial[Title/Abstract]) OR clinical trials[MeSH Terms] OR clinical trial[Publication Type] OR random*[Title/Abstract] OR random
allocation[MeSH Terms] OR therapeutic use[MeSH Subheading])
specific/narrow 93%/97% (randomized controlled trial[Publication Type] OR (randomized[Title/Abstract] AND controlled[Title/Abstract] AND trial[Title/Abstract]))
diagnosissensitive/broad 98%/74%
(sensitiv*[Title/Abstract] OR sensitivity and specificity[MeSH Terms] OR diagnos*[Title/Abstract] OR diagnosis[MeSH:noexp] OR diagnostic *
[MeSH:noexp] OR diagnosis,differential[MeSH:noexp] OR diagnosis[Subheading:noexp])
specific/narrow 64%/98% (specificity[Title/Abstract])
etiology
sensitive/broad 93%/63% (risk*[Title/Abstract] OR risk*[MeSH:noexp] OR risk *[MeSH:noexp] OR cohort studies[MeSH Terms] OR group*[Text Word])
specific/narrow 51%/95%((relative[Title/Abstract] AND risk*[Title/Abstract]) OR (relative risk[Text Word]) OR risks[Text Word] OR cohort studies[MeSH:noexp] OR (cohort[Title/Abstract]
AND stud*[Title/Abstract]))
prognosissensitive/broad 90%/80%
(incidence[MeSH:noexp] OR mortality[MeSH Terms] OR follow up studies[MeSH:noexp] OR prognos*[Text Word] OR predict*[Text Word] OR
course*[Text Word])
specific/narrow 52%/94% (prognos*[Title/Abstract] OR (first[Title/Abstract] AND episode[Title/Abstract]) OR cohort[Title/Abstract])
clinical prediction
guides
sensitive/broad 96%/79% (predict*[tiab] OR predictive value of tests[mh] OR scor*[tiab] OR observ*[tiab] OR observer variation[mh])
specific/narrow 54%/99% (validation[tiab] OR validate[tiab]