When you are doing research you will need to experiment with different search strategies. Boolean Operators can help save you time because they can improve your search results and make your searching more efficient. It's important to know that Boolean Operators are the underlying logic in library databases including Omni, article indexes and even search engines such as Google Scholar.
Most databases provide the option to select Boolean Operators on the Advanced search screen, so all you have to do is select the operator you want from a drop down box between search boxes. In Google Scholar, the Boolean Operators are available from the Advanced Search.
In the following example from Philosopher's Index, enter each concept of keyword on a separate line, leaving the default AND between concepts (to view a larger version of this image, right click on image and choose "open image in new tab."
Boolean Operator: AND
Use AND when your research topic has more than one key term that must be present in all of your search results. In this example, use it to link the key terms plato AND symposium AND love so that all three concepts appear in all of your search results. Searching with AND gives you fewer results.
Boolean Operator: OR
Use OR when there are other terms that could also be used to describe the topic, including synonyms, related terms or words and phrases that have similar meaning. In this example, use OR to locate articles that contain either love OR sex OR gender. Searching with OR gives you more results.
Boolean Operator: NOT
Use NOT when you want to exclude results that contain a particular word, phrase, or topic, or when your research topic is often closely associated with another concept you do not want information about. Using NOT will eliminate all search results that include the unwanted concept. Use NOT sparingly, if at all, as it could exclude results that are ultimately relevant. Searching with NOT gives you fewer results.
Databases such as Philosopher's Index have an option to limit your search results to Peer Reviewed.
Apply this limit, and also a limit to Document Type - Journal Article.
You can narrow your search results by limiting where the database will search for your search terms.
I recommend limiting to Abstract if your searches are returning too many results where the relevancy is questionable: