Some article databases allow you to search using "subject headings" or "controlled vocabulary". These vocabulary come from a predefined list of words used by experts to "tag" each article in the database. This can be a powerful way to search for information because it can assist you in finding articles where authors use different words, or spellings of words that describe the same thing.
"Keywords", are words you search for in the database that are not part of the controlled vocabulary. When you search for a keyword in a database, the database will search for the exact word and spelling of the word that you are searching for. Keywords can be useful when searching for concepts that do not have subject headings, or if a concept is so new that no subject headings have yet been created, etc.
In some cases it can be good to combine keywords and subject headings to ensure a comprehensive search.
Medical databases like Ovid Medline and PubMed use subject headings called MeSH; whereas Embase uses Emtree. Some engineering databases like Compendex also used controlled vocabulary.
There are many resources out there that will help you learn about searching using subject headings. We will talk about using MeSH in MEDLINE in your library workshop. Queen's University has an excellent guide for using MeSH in MEDLINE. Select the link below.
Some medical databases, like MEDLINE, PubMed and Embase, can be searched using a sophisticated search string that includes synonyms of all of your concepts connected using Boolean operators.
First, combine your concepts using the Boolean operator AND. This search will retrieve articles that have both of the concepts. If for example you wanted research about your pet cat and how much it sleeps you would search for:
sleep AND cat
Next, brainstorm all of the synonyms (MeSH terms and keywords) for your concepts.
Cat: feline, feline domestica
Sleep: nap, rest
Then, combine all of your synonyms for a single concept using the Boolean operator OR. This will search for articles with any of the terms.
cat OR feline OR feline domenstica
Databases use Boolean operators using an order of precedence:
Use (brackets) around your synonyms in your search before combining your concepts with the Boolean operator AND.
(cat OR feline OR feline domenstica) AND (sleep OR nap OR rest)
Point of Care tools can help answer clinical questions quickly. You can also find information for patients that is easy to understand and written for non-medical people.
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