How can I use this?
You can make your keyword searching even more powerful using Boolean Logic, which uses special terms called 'operators' to include and exclude results from your search. To start, you should be familiar with these two important two Boolean operators:
OR
This operator serves to broaden a search by capturing synonyms or variant spellings of a term. If you want to find any of the following words in the search, use the Boolean operator OR.
Example: green crab OR shore crab
In other words, use synonyms for your concept joined by the OR operator.
This operator narrows a search by capturing two or more ideas or concepts. If you want to find both of the following words in the search, use the Boolean operator AND.
AND
This operator narrows a search by capturing two or more ideas or concepts. If you want to find both of the following words in the search, use the Boolean operator AND.
Example: green crab AND pH