The AND operator:
obesity AND soft drinks
The OR operator:
soda pop OR soft drinks
The NOT operator:
soft drinks NOT sports drinks
WARNING:Use NOT with caution. It could remove relevant results that discuss both the topics- soft drinks and sports drinks.
AND (Use to combine concepts)
Type in one concept per search box.
Use AND between the search boxes. The database will find articles that cover both concepts.
OR (use with synonyms or related words)
Type in one keyword per search box.
Use OR between the search boxes. The database will find articles that cover either keyword.