Boolean operators are named for George Boole (1815-1864), an English Mathematician and Philosopher. Boolean Algebra and Symbolic Logic both derive from his work. Boole is generally considered the father of modern computer science. Most electronic indexes (databases) require the use of Boolean operators in parsing search terms, although this is not always apparent. Boolean search statements are incredibly powerful in retrieving what you need provided 1) the statement is formatted correctly and 2) your choice of search terms is correct for the topic you are researching.
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.
Try the Search Strategy Builder, which will create searches out of keywords that you supply!
Example search statements using Boolean operators and symbols:
Rhodococcus fascians pistachio* AND "bushy top syndrome"
(Rhodococcus fascians OR Corynebacterium fascians) AND (pistachio*) AND ("bushy top syndrome" OR "leafy gall syndrome")
(Rhodococcus fascians OR Corynebacterium fascians) AND (pistachio* OR "pistacia vera") AND ("bushy top syndrome" OR "leafy gall syndrome")
(Calcium AND milk) NOT goat
child* AND anxiety AND (exercise OR "physical activity")
Read more about Boolean searching here: http://www.nlm.nih.gov/bsd/disted/pubmedtutorial/020_350.html
Truncation: A symbol, specific to the search interface, which allows the retrieval of all endings for the specified base word. An asterisk (*) isoften used. For example, child* would retrieve records with children, childish, 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 questio mark is often used. For example, wom?n would retrieve records with women or woman.
: Adding quotation marks around a phrase, such as will tell the database to search for these words together, rather than separately. *This will narrow your search (get you less results), so keep that in mind, but in some cases it's the best way to find results with a specific phrase of interest - especially when the words in that phrase are common on their own (like physical and activity).
Read more about these sorts of tricks here: https://guides.lib.vt.edu/gettingstarted/advancedsearching