To get the most satisfactory results from a search engine you need to know about Boolean operators and how to use them. Boolean operators are AND, OR, NOT. They join other words or phrases together in a specific way to either expand or narrow down your search.
Truncation is another way of expanding your search to gatheras much relevant information as possible.
By truncating a word you enable the search engine to find from the root of the word the widest possible hits eg. politic* will give you all the following words politics, political, politically, politician, politicians in an article.
The asterisk (*) used in this example is not universal. Some databases use a question mark (?) while others use different symbols. Ask your information librarian about the different uses.