Use Boolean operators
The Boolean operators AND, OR, and NOT can help you combine concepts, as well as helping you to expand or narrow your search.
Use subject terms or descriptors.
If you find an article on the topic you are interested in, look at the subject terms or descriptors that are listed in the record for the item. These terms are standard within the database, and often can help you locate more articles on that topic.
For example, if you are looking for articles on African Americans in Chicago politics and enter "African Americans" as a search term, you will likely get some results. But looking at the subject terms within some of the records, you may notice that the database uses the descriptor "blacks". Using that as a subject/descriptor may expand the number of search results.
Some databases, such as PsysINFO or Medline, will have a thesaurus feature built in the database, which will point you to the best subject terms. Take advantage of these features when they are available.
Use limits
Most databases provide an option to limit your search. These limits can include language, source types, publication date, scholarly (peer reviewed) journals and full text only. If you find yourself getting too many hits, or would like to eliminate certain types of records, set your limits and try again.
Use truncation and wildcards when applicable.
Most databases provide an option to use wildcards or truncation. This will help you search variations of words that may be important for your search.
These symbols can vary from database to database, so check the "Help" or "Search Tips" options in the database you are searching to find the best one for your needs.
Rather than typing a full sentence or question into a search box, using Boolean operators can help you create an efficient and effective database search.
Tips & Tricks for Database Searching
Truncation: A symbol, specific to the search interface, which allows the retrieval of all endings for the specified base word. An asterisk (*) is often used. For example, child* would retrieve records with children, childish, childhood and every other word that begins with the root word "child."
Wildcard: A symbol, specific to the search interface, which allows the retrieval of various spellings of a word. A question mark is often used. For example, wom?n would retrieve records with women and woman.
Quotation marks: To search for an exact phrase with the words together, in the order you wish to find them, add " " quotation marks around the phrase, such as "physical activity" versus finding an article about physical education and an activity for elementary school students.
Parentheses: Help to keep search terms together, such as searching for synonyms of a concept while also searching with another Boolean operator, such as measles AND (epidemic OR "disease outbreak")
Example Boolean search statements using symbols & parentheses:
child* AND anxiety AND (exercise OR "physical activity")
Ischemia AND (Stroke OR Infarct)
alzheimer* AND malnutrition AND elderly
alzheimer* AND malnutrition AND (elderly OR aged OR older adults)
alzheimer* AND (nutrition OR diet OR malnutrition) AND (elderly OR aged OR older adults)
(delirium AND surgery) NOT mice
Research Database Fields
Default - Most research databases have a default search that looks for your keywords in a variety of places. Depending on the database, this often includes the title of documents in the database, the abstract (summary) of the documents, and the 'subject headings,' or 'index terms' that the database creators have used to tag the documents in the database. *However, a database's default search may also look in: the journal / source title, the full text of documents included in the database, document reference lists, and other areas.
Title / Document Title - Target your search to those documents that have your keywords in their title.
Abstract - Target your search to those documents that have your keywords in their abstract / summary paragraph.
Title & Abstract - Target your search to those documents that have your keywords in their title.
'Subject Headings' / 'Index Terms' - Target your search to those documents where your keywords match up with the index terms or subject headings that the database creators have used to tag the documents with a significant focus on that topic or topics.
Boolean operators
AND: narrows search results; both terms that you connect with AND must be somewhere in the bibliographic record for that record to be retrieved. AND narrows a search and retrieves fewer articles. For example:
stroke AND paralysis
--> search results must include both terms
OR: only one of the search terms combined with OR is required for the bibliographic record to be retrieved. OR broadens a search and retrieves more articles. For example:
stroke OR ischemia OR brain infarction
--> search results must include at least one of these terms
NOT: excludes a particular subset, category, or term. NOT requires the presence of one search term and the exclusion of another.
ischemic stroke NOT hemorrhagic stroke
--> eliminates search results terms on hemorrhagic stroke but includes results on ischemic stroke
Learn more about Boolean searching at the PubMed Boolean Tutorial.