Basic Training 2023 for PhD students

Document Retrieval
Nagoya University Graduate School of Medicine
Medical Library
Ext： 2509
E-mail： med@nul.nagoya-u.ac.jp

Nobuyuki Hamajima, MD, PhD, MPH
Emeritus Professor, Nagoya University
Advisor, Kishokai Medical Corporation※As of 2021

Purposes
1. Learn the structure of databases used for

medical researches, and master the skill toobtain the information of references
needed for own research effectively.
2. Learn how to obtain the references basedon the information from the database.

Contents and requirements
Title of video
Address of Library DirectorBasic and strategy of document
retrieval
PubMedWeb of Science
How to obtain the references
The other databases

Requirements forcrediting• See all videos• Answer the Tests in thecourse through TACT• Submit your answer sheetof the final assignment andan evaluation sheet by thedeadline

When you have questions, send your inquiry to med@nul.nagoya-u.ac.jp

BASIC AND STRATEGY OF
DOCUMENT RETRIEVALContents
1.

Research/Clinical Question： PICO/PECO

2.

Thesaurus

3.

Verification of results and correction ofconditions of retrieval

4.

Outline of medical databases

5.

Access to databases

Contents
1.

Research/Clinical Question： PICO/PECO

2.

Thesaurus

3.

Verification of results and correction ofconditions of retrieval

4.

Outline of medical databases

5.

Access to databases

What is PICO/PECO
PI(E)COP
I（E）

Meaning
Patient, Problem, Population
Interventions/Exposure

C

Comparisons, Controls, Comparators

O

Outcomes

Formularization of request according to PICO/PECO
It helps①to make the purpose clear②to put the retrieval keywords in order③to select an appropriate study design

Example of PICO/PECO
When you research “Effect of mucolytic drugs
to patients with stable chronic obstructive
pulmonary disease”
Component of PICO

Possible retrieval termP

Patients with stable chronic
obstructive pulmonary
obstructive disease

COPD/chronic bronchitis

I

Mucolytic drugs

Mucolytic

C

Placebo (and latest besttherapy)

PlaceboO

Number of deteriorated
patients and death

Exacerbation/mortality

Use of PICO/PECO
Comprehensive search such as systematic review•

Search with P AND I .

•Be aware that there is no O in the title or abstract.

•In case of too many hits, narrow down them byadding study design.

Effective retrieval for the clinical problems•

Search with P AND I AND C AND O.

•In case of no hits, try it using another synonyms.

Use of thesaurus is effective in either case.

Contents
1.

Research/Clinical Question： PICO/PECO

2.

Thesaurus

3.

Verification of results and correction ofconditions of retrieval

4.

Outline of medical databases

5.

Access to databases

Roles of thesaurus••

Vocabulary set in database

Conversion of synonyms to controlled
vocabularies•

Making a stratified structure•

MeSH in PubMedTerms used in references

Controlled vocabularies

Stucture in thesaurus

UpperLower

Effects of thesaurus••

Use of controlled vocabularies prevents
drops from retrieval due to the different
expression.
Only relevant references could be retrieved.
Thesaurus
retrieval

A fewer hits with a fewer unrelated references

Keyword retrieval A more hits with a more unrelated references

Limitations of thesaurus•

No thesaurus in recent references•

No controlled vocabularies for new terms

出典：“米国国立医学図書館（NLM）、医学件名標目表（MeSH）2021年版の適用をはじめとした医学学術文献データベースMEDLINEの年末更新処理を実施”．カレントアウェア
ネス・ポータル．2020-12-9．https://current.ndl.go.jp/node/42724，(参照 2021-3-32)

Subheading•

Subheading indicates the field the word used.

•Example 1: Chemotherapy for liver cirrhosis inPubMed•

MeSH

Liver Cirrhosis

Subheading

drug therapy

Example 2: Possibility of adverse event of t-PA
administration to acute cerebral embolism→Stroke[MeSH] AND Tissue Plasminogen Activator[MeSH] AND Intracranial Hemorrhages / chemically in
duced[MeSH]

Automatic mapping•

Automatic guidance to appropriate controlled
vocabularies for an input natural term•

OR retrieval for natural language andcontrolled vocabularies•

Retrieval solely by natural language in case ofno controlled vocabularies
PubMedDatabases without thesaurus
1. Collect synonyms•

Retrieval using synonyms by OR function

Ex：cancer OR tumor OR neoplasm OR…

ANDORNOTA AND B

A OR BA NOT BAA

A

B

B

B

Databases without thesaurus
Use of partial match•••

When a part of retrieval terms is input, references
including the part can be retrieved.
*, ?, $, etc. can be used before and after thewords. The symbols are unique in each database.

Right-Hand Truncation enzym＊→ enzyme, enzymes

Internal Truncation

Hof＊man＊→ Hofmann, Hoffman

Left-Hand Truncation＊old→ told, household, bold

Contents
1.

Research/Clinical Question： PICO/PECO

2.

Thesaurus

3.

Verification of results and correction ofconditions of retrieval

4.

Outline of medical databases

5.

Access to databases

Drop and noise
Drop
Noise

Necessary references are not retrieved.
Inclusion of unnecessary references

Necessaryreferences

Retrievedreferences

Appropriate
Drop

Noise

Available databases

No drops？
Modification of thesaurus（Keywords）•

Adding synonyms using OR

Examine upper/lower terms in thesaurus•

Upper terms = retrieval in a wider range•

Retrieval with lower terms

Pay special attention to recent data and old data•

No thesaurus, no registration of reference data, or so.

Many noises？
Phrase (idiom) retrieval••

Retrieval as an idiom with more than 2 words
Ex.“lung cancer”
The symbol is unique in each database.

Restriction by item other than keywords•Subheading•

Study design•

Age of subjects, etc.

Contents
1.

Research/Clinical Question： PICO/PECO

2.

Thesaurus

3.

Verification of results and correction ofconditions of retrieval

4.

Outline of medical databases

5.

Access to databases

Characteristics and usage（Journal databases)
Database

Characteristics

PubMedRegistration mainly including
English references

Web of Science• Selected from PubMed• With the information on
citation, clearing the relation
between studies

EBM is explained in the video of “The other databases”.

Contents
1.

Research/Clinical Question： PICO/PECO

2.

Thesaurus

3.

Verification of results and correction ofconditions of retrieval

4.

Outline of medical databases

5.

Access to databases

The site of medical library••https://www.med.nagoyau.ac.jp/medlib/index_en.html
Bookmark this page in your browser.

Use from the off-campus•

Select the below at homepage of libraryhttps://www.nul.nagoya-u.ac.jp/db/DBannai/ezproxy/index.html••

Cochran, Web of Science, and PubMed arealso available at the page.
Please, logout at the end of your work.

This is the last slide of “Basic and strategy ofdocument retrieval”
Go on the next video.

If you have questions, please send them to
med@nul.nagoya-u.ac.jp