Carrying out a literature search- a brief guide
|
Contents
1. Clarify Your Topic
Take time to consider the exact information you
are looking for. If possible try to rephrase your topic as a question.
Breakdown the topic into its major concepts such as:
1.
the patient or problem being addressed
2.
the intervention or treatment being considered
3.
comparative treatments if relevant
4.
desired clinical outcomes of
eg Nut allergies in children
|
Patient |
Exposure |
Outcome |
|
Children |
Nuts |
Allergy |
Try to think of alternative words, spelling
variations or synonyms for each concept:
|
Children: |
child,
paediatric, pediatric |
|
Nuts: |
nuts/peanuts |
|
Allergy: |
hypersensitivity/allergy/intolerance |
2. Select Database(s)
The following databases are available through
healthcare libraries in
Healthcare Database(s)
|
Medline |
Largest
biomedical database |
|
EMBASE |
Biomedical
- |
|
AHMED |
Allied
and alternative medicine |
|
PsycINFO |
Psychology
and related disciplines |
|
HMIC |
Management
and community |
|
BNI |
Nursing
- |
|
CINAHL |
Nursing
and Allied Health |
Specialist Review Sources:
(i) the Cochrane Library
A database containing systematic reviews and other
information that will assist in making diagnostic treatment and other health
care decisions.
(ii)
Clinical Evidence.
A monthly updated directory of evidence on the
effects of common clinical interventions. It summarises the best available
evidence, and where there is no good evidence it says so.
3. Conduct The Search
There are two main methods of searching, and
although different databases have different features, the principles of
searching will remain the same:
(i)Subject
searching
Databases such as Medline use a controlled
vocabulary to index articles. Each article will have a number of subject terms
(Medical Subject Heading - MeSH - in Medline)
assigned to it to represent the key concepts it covers. Searching using a
subject term should only retrieve material relevant to the concept.
Advantages
- Should ensure retrieval of
relevant material
- Standardizes
terminology/spelling
- Allows a term to be searched
with its more specific headings (exploding)
How do I know which subject heading to use?
- Click on the Thesaurus button
- Type a word in the Subject box
- Click Go to Subject
The index will display your term or the nearest
match. Select the appropriate heading(s) by clicking the box next to it.
Selecting Explode Search Subjects will search for
your heading, plus any narrower (more specific headings. Click Checked
Subjects.
|
Concept |
Subject
Heading |
|
Nuts |
Nuts |
|
Allergy |
Hypersensitivity |
(ii)Text word Searching
If your concept does not have an appropriate
subject heading, you can search for your term as a textword.
The computer will search the whole record for an exact match of the term.
This method will not guarantee retrieval of
relevant material e.g. "back" will not distinguish between the human
back and the word "back" in any other context.
Textword searching will often retrieve irrelevant material,
particularly for frequently used terms.
As a general rule, use textword
searching when:
- There is no appropriate
thesaurus term (eg for an uncommon term,
acronym, institution), or
- If you wish to broaden your
thesaurus search to include alternative words for more exhaustive
retrieval.
(iii)Truncation and
wildcard
Truncating the term can also allow for spelling
variations eg Allerg$ will
allow for allergy, allergic, allergen.
Remember
that the method(s) you use will depend on:
- the nature of your
topic
- how exhaustively
you need to search
- how much time you
have available
4. Combine Search Results
Once you have searched for each term and created
separate sets, the next step is to combine them using the operators AND and OR:
Hypersensitivity(MeSH)
OR allerg$ (freetext)
Will search for references with either
hypersensitivity as a subject heading or for references containing the stem
"allerg-", or
for references containing both:
Once sets have been created for each concept, they
must then be combined using AND:
Here the set representing Nuts or its alternatives
is combined with the set representing hypersensitivity or its
alternatives, to create the intersection between
the two i.e.Only references covering both concepts
together.
5. Refine Search
If you have too few results you may need to
broaden your search by
- Using additional
synonyms/alternatives
- Using broader subject headings
in the thesaurus and/or explode subject headings
- Including all subheadings with
thesaurus terms
- Combining thesaurus and free
text terms
6. Limit Results
Limiting functions will allow you to restrict your
results by various parameters such as:
Age group
- e.g. child or adult or more specific (infant or middle aged). Hence the
search for nut allergies in children could be limited to all child age
groups, without needing to search for the term children.
Publication type - e.g. Reviews, meta-analyses, guidelines. It is also
possible to limit specifically to review types academic and tutorial,
which tend to be of a higher quality. Always check the Cochrane Library for the
highest quality systematic reviews, as these are more extensive than in
Medline.
Language -
use with caution as foreign language abstract articles may be relevant and may
provide an English abstract.
7. Further Assistance
For further information and advice on searching
please contact your healthcare library. Athens Passwords for access to the
databases can be arranged and training sessions are also available.
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