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Searching the Literature: A Guide to Comprehensive Searching in the Health Sciences

Students and researchers in the health sciences are often required to conduct comprehensive searches of the literature. Follow the steps in this guide to learn how this process works.

Textwords vs Subject Headings

For a comprehensive search, always search both subject headings and textwords for each concept.


Textword searching means using terms you choose yourself to search the "record" of a database. The record DOES NOT include the full-text article. It mainly includes the TITLE, ABSTRACT, and AUTHOR-PROVIDED KEYWORDS. Textwords are often referred to as keywords.

Subject heading searching means using preassigned terms to search for articles labelled with that term. Each database uses its own subject headings - MEDLINE's are called MeSH.


Sometimes subject headings and textwords are the same, but often they aren't. The MeSH heading in MEDLINE for support groups is Self-Help Groups. Using only the textword "support groups" will leave out some articles tagged with the subject heading, but using only the subject heading will leave out some articles that use the textword.

Why use Subject Headings (aka a Controlled Vocabulary)?

Subject Databases use "controlled vocabularies" made up of subject headings, organized hierarchically. Subject headings solve 2 major problems we encounter when relying solely on textword searching: Synonyms and Ambiguity. 


Pet Therapy = animal assisted therapy, therapy dog, therapy dogs, equine-assisted therapy, therapy animals, etc. 

If you only searched for 'pet therapy', you'd miss all articles that use 'therapy dog' to describe that concept. It's very difficult to think of all the potential ways of expressing a concept. 


Pet therapy = animal assisted therapy, Positron emission tomography

If you searched for 'pet therapy', thinking you'd retrieve only articles about therapy animals, you'd have to sift through quite a bit of literature on PET imaging. 

So, to solve these problems, you could search the subject heading for the concept of pet therapy. In Medline, the Mesh is Animal Assisted Therapy. In CINAHL it's Pet Therapy. 

Different Subject Databases use Different Controlled Vocabularies

Search strategies MUST be customized for each database:

  • databases use different subject headings to describe the same concept
  • a database can't be searched effectively unless the correct subject headings are used
  • each database requires it's own, unique search strategy 
Database Controlled Vocabulary
PsycINFO APA Thesaurus
Sociological Abstracts Thesaurus of Sociological Indexing Terms
AMED AMED Thesaurus

Textwords: Codes and Tips

Textword Syntax Cheat Sheet



Proximity/Adjacency Operators

Field Codes (a selection)


Truncation symbols can be used to search for endings of words.

Note: Be careful when truncating 3-letter words (because cat* = catastrophe, cataclysmic, catatonic)


The proximity operator searches for terms near each other.

Note: Adjacency runs in both directions. Searching for heart ADJ5 attack will search for ‘heart attack’ or ‘attack of the heart’, etc (although the database may not find anything).


Tell the database where to look for your textwords.


Increase the efficiency of your querying by forcing order of operations. 

OVID Databases
(e.g. Medline, Embase, PsycINFO, AMED)


* or $ or  :

famil*= family OR families OR familiar OR familiarity OR familicide, etc




(where ‘n’ is a number from 1-99 or left blank)

oil adj olive = the two words side by side, in either direction

oil adj2 olive = olive oil, but also “olive and canola oil”

 .ti = title
 .ab = abstract
 .tw = title OR abstract
 .kw = author-provided               keyword exact
 .kf = word in author                  provided keyword
 .pt = publication type
 .mp = multipurpose,                 includes subject               heading

((Oil OR oils) ADJ3 (grape* OR olive OR canola OR sunflower)).tw,kf

EBSCO Databases (e.g. CINAHL)



NOTE: (*) may also be used

between words to match any word.


a midsummer * dream = a midsummer night’s dream



(where ‘n’ is a number from 1-99 or left blank)



 TI = title
 AB = abstract
 TX = all text
 IN = instrumentation
 SO = publication name

TI ( (oil OR oils) N3 (grape* OR olive OR canola OR sunflower) ) OR AB ( (oil OR oils) N3 (grape* OR olive OR canola OR sunflower) )

ProQuest (e.g. Sociological Abstracts, ASSIA)




NOTE: (*) can ALSO be used at the
beginning (left-hand truncation),
the end (right-hand truncation),
or in the middle of a word.


*old = told, household, bold,

(note: must specify a number, cannot leave blank)

 TI = title

 AB = abstract

ti((oil) NEAR/3 (grape* OR olive OR canola OR sunflower)) OR ab((oil) NEAR/3 (grape* OR olive OR canola OR sunflower))

Example Textwords (OVID Medline)

Super precise textword search:

  • Treatment goal – 9 hits

Balanced textword search:

  • (goal* OR priority) ADJ3 (set* OR plan* OR establish*).tw – 11914 hits

Sensitive textword search:

  • ((goal* or priorit* or target*) ADJ3 (agree* or negotiate* or convers* or discuss* or propos* or develop* or formulat* or elaborate* or establish* or identif* or write or written or state* or specif* or construct* or manag* or direct* or orient* or cent?red or achiev* or evaluat* or attain* or facilitat* or misalign* or align* or care or outcome* or plan* or set* or health or select*)).tw.– 274896 hits