Check out these excellent pages from Journalist's Resource containing tips and resources for topic research.
Excellent Research Tips from Journalist's Resource
Whenever you want to search for two (or more) concepts you should combine those terms with AND. Example:
women AND media
When you want to search for two related concepts, or a concept that might have more than one name, combine them with OR
(women or gender) AND media
Another search tool is the truncation symbol, usually a star or asterisk. When you put the truncation symbol at the end of a word, it tells the database that you'd like it to find all the places where any form of that word occurs. For example, if you search for:
blog*
your search results will include:
blog blogs blogger blogging