Multiple terms: term1 term2 red apples returns results with all terms like: Fructose levels in red and green apples
Precise match in quotes: "term1 term2" "red apples" returns results matching exactly like: Anthocyanin biosynthesis in red apples
Exclude a term with -: term1 -term2 apples -red returns results containing apples but not red: Malic acid in green apples
