Search Tips
Determine whether the database considers multiple words as a single phrase, or a combination of words connected by OR (any of the words) or AND (all of the words). Ex. Academic Search Complete's default search is a phrase search (less results)—put each word into a separate box to get more results.
Use truncation symbols. Each database has its own truncation symbol (*, ?, $, #, !). Ex. engineer* will retrieve engineer, engineers, engineered, engineering, etc.
Use controlled vocabulary (or subject headings, descriptors, thesaurus) to ensure that items being retrieved are specifically on the topic of interest.
Use refine results features to narrow down results. Refine by document, publication, or literature type OR add terms like "survey paper" or "overview" into a keyword search box to find review articles.
For more tips on database searching, see the Biomedical Library's Dissecting a Database website.
Using OR properly when constructing Boolean searches
Use the Boolean OR operator when you are listing synonyms or related concepts. This is typically done within a single search field.
Example 1. This an ineffective use of OR. This search retrieves every time “organism” appears in the database, even if it does not relate to GMOs. You get 178,586 results, mostly irrelevant ones.
This following is an effective use of OR. The search is looking for “food” OR “organism” anytime genet* and modif* also appears. Now you only get 13,083 results as opposed to 178,586 in the previous search.
Example 2. With the following ineffective use of OR search you get 31,596 results.
If you only search the word “license” you get 29,822 results.
This shows that first search is mostly useless since 29,822 of the 31,596 results come from any mention of the word license - but not necessarily anything related to genetics. These 29,822 articles could be about driver’s licenses, hunting licenses, poetic license, etc. They are diluting the result set full of irrelevant results. A better search would be “gene” in the first box connected with AND and “patent OR license” in the second box, that way you would only get articles that have the word “gene”, and also “patent” OR “license”.