Look for options to refine your search by type of source, full text, date, etc.
Use wildcard characters. If searching for economic conditions, type the word econ* with an asterick. That will return economies, economic, economist and any word that starts with econ.
Try using Boolean operators: AND, OR, NOT. For example: "World’s Columbian Exposition" AND "labor."
Use quotation marks to search for the words that are next to each other.