When it's important for your keywords to be found together and in a certain order, such as the phrase "fossil fuels," make sure to use quotation marks around the phrase. If you were to type in fossil fuels without the quotes, the results you get will include articles or books that mention fossil, fuels, and sometimes fossil fuels. Using quotes narrows your results down to the exact phrase you need.
"Fossil fuels" = fossil fuels
Fossil fuels = fossil, fuels, fossil fuels
Sometimes, a word you want to use as a keyword might have variations. To search for the possible variations, use a truncation symbol, such as the asterisk * symbol.
For example, if you're looking for research about the effect of something, typing effect* into the search box of a database will bring results for anything that starts with the word effect, including effect, effects, effectual, effective, etc.
Effect = effect
Effect* = effect, effects, effective, effectual, etc.
Wildcard symbols are like truncation symbols, but wildcards help you find variations of words in the middle of a word rather than at the end of a word. The most common wildcard symbol is the question mark ? symbol.
For example, if you need to find articles or books about women, it would be helpful to search for both the words woman and women. You can actually search for both variations at the same time using a wildcard symbol. Typing wom?n in the search box of a database or the library catalog will bring results for both woman and women.
Women = women
Woman = woman
Wom?n = woman, women