Use no punctuation. Some punctuation is used. Ignore parentheses but include the hyphen in hyphenated words. Commas are not used. It is possible to combine two or more words in a single keyword search by using operators.
Logical operators show logical relationships between keywords.
This kind of search is useful when two words have the same general meaning and you want information pertaining to both. Or usually retrieves the largest number of records. The not operator limits what you retrieve. It is best utilized when your subject includes a topic not directly related to your research. They are often prepositions or articles.