An introduction to Medline (CMM2)

Medical Subject Librarian Team

Session outline and outcomes

The session will include:• some information about the Medline database• the components and techniques of database searching• a demonstration of a typical Medline search• a practical exercise

By the end of the session you should have a better understanding of:

• the formulation of a successful database search strategy• the Medline indexing process• how to interpret and use your search results

Why?

• Why have this session?

• Why use journals?

• Why use databases?

• Specifically, why use Medline?

Medline - some facts and figures

• Database provided by the US National Library of Medicine (therefore has a US bias)

• Content includes basic research and clinical sciences

• Contains over 14 million records• Indexes over 4,600 core biomedical journals• Searchable back to 1950• Updated weekly

Using Medline via the OvidSP platform

• Lecturers will often refer to searching Medline via PubMed

• Searching Medline via OvidSP allows you to see more clearly how you achieve your results

Medline: an example search

Let’s say we want to find journal articles published on the subject of:

Brain tumours related to mobile phone use

Before starting your search ask yourself:

• What are my keywords? • Are there any other ways to spell the keywords? • Are there any other words which mean the same

thing (synonyms)?

• Are there any related keywords I want to include?

Identify keywords, synonyms and related keywords

Brain cancerIntracranial tumour…malignancy…carcinoma…neoplasm…tumor

Cellular phoneCellphoneElectromagnetic fieldsRadio wavesRadiation

Mobile phoneBrain tumour

Brain tumours related to mobile phone use

Combine your terms using Boolean logic

or Intracranial

tumourBrain tumour

To combine synonyms use search operator ‘or’

Combine your terms using Boolean logic

and Mobile phonesBrain tumour

To combine concepts use search operator ‘and’

Combine your terms using Boolean logic

Mobile phones not Hearing loss

To exclude unwanted terms use search operator ‘not’

Combine your terms using Boolean logic

Brain tumour

orIntracranial tumour

orBrain neoplasm

Mobile phone

orCellular phone

orRadiation

and

Your combined search will start to look something like this:

Medline: methods of searching

• Search by Medical Subject Headings (MeSH)• Search by text words

Both approaches needed for good quality searching

Medline – MeSH searching

What is a ‘MeSH’ search?• MeSH = Medical Subject Headings (a thesaurus)• Indexer reads entire article (not just the abstract) and

assigns headings from this thesaurus to describe its contents

Why use it?• Synonyms come under one preferred heading

(e.g. ‘brain neoplasms’ will retrieve articles on brain or intracranial cancers, tumour, tumor, carcinoma etc)

http://metalib.bris.ac.uk

Select Find database

Select Find database

Find database

medline

Find database

Click on Medline link

Click on Medline link

University of Bristol Single Sign-on

The OVID platform

Select Medline 1950 to presentSelect Medline 1950 to present

MeSH: select Advanced Ovid Search tab

Select Advanced Ovid SearchSelect Advanced Ovid Search

Use Ask a University of Bristol Librarian to get feedback on your search

Use Ask a University of Bristol Librarian to get feedback on your search

MeSH: entering a search term

brain tumour

MeSH: mapping display

Check the Scope NoteCheck the Scope Note

MeSH: scope note

Back to Previous PageBack to Previous Page

MeSH: select a term

Choose Brain NeoplasmsChoose Brain Neoplasms

MeSH: the tree structure

Explode your termExplode your term

Click ContinueClick Continue

MeSH: subheading display

Choose Include All Subheadings*

Choose Include All Subheadings*

* Think inclusively at the early stages of a search BUT note down any subheading codes for potential later use

* Think inclusively at the early stages of a search BUT note down any subheading codes for potential later use

Click ContinueClick Continue

MeSH: first search result

Click Search History to expandClick Search History to expand

MeSH: combining terms 1

1 and 2

MeSH: combining terms 2

Searching by text word searches for the exact words in the titles or abstracts of all papers on the database

If MeSH is so good, why use the text word option?

• If the topic is a new one there is unlikely to be a MeSH term

• Sometimes the MeSH term is too general to be of use• Sometimes the appropriate MeSH term will elude you• Helps overcome possible errors or omissions – indexers

are only human!

When to search by text word

• * Pollut* - will give you pollute, polluter, polluting, pollutant, pollutants, pollution

etc

$ also works in this way in OvidSP

• # Often useful with American spelling - e.g. ioni#ation will find both ionisation and ionization (represents a single character)

• ? colo?r finds color or colour (zero or one character)

Text word searching: wildcards

Text word searching 1

Select Search FieldsSelect Search Fields

Text word searching 2

(brain or intracranial) adj2 (cancer* or tumo?r* or carcinoma* or malignan* or neoplasm*)

(brain or intracranial) adj2 (cancer* or tumo?r* or carcinoma* or malignan* or neoplasm*)

Select Text WordSelect Text Word

Text word searching 3

(1 or 4) and (2 or 5)

Text word searching 4

How to refine your results

Too few hits? • Think of all possible MeSH and text word terms (synonyms, alternative terminology/spelling) for each concept and link the related terms using OR

• Check your spelling• ‘Explode’ your mesh searches and include all subheadings • Use truncation when conducting text word searches

Too many hits? • Use more precise search terms• Add additional search terms to existing search sets using AND• Restrict your mesh searches to ‘focus’• Specify subheadings• Apply limits

MeSH: restricting to focus

*3

MeSH: specifying a subheading

1/ep

MeSH: specifying a subheading

Select Additional LimitsSelect Additional Limits

MeSH: limits

MeSH: additional limits

Practical work

• In pairs or threes, work through the question sheet

• Take your time and work collaboratively - the key to the practical work is understanding what you are doing, not the speed in which it is completed

Any questions?

For further help:Contact the Medical Subject Librarian team:

• Email: medical-librarians@bristol.ac.uk(or use the ‘Ask a University of Bristol Librarian’ link in Medline)

• Telephone: (0117) 331 1504