Perhaps you should try some spelling variations:
"behavioural economics" » "behavioral economics"
"behavioral economic" » "behavioral economics", "behavioral ecology"
"behavior economics" » "behavior economic", "behavioral economics", "behavioural economic"

You may be able to get more results by adjusting your search query.

• If you are trying to use Boolean operators, they must be ALL CAPS: (((("behavior economics") OR ("behavioral economic"))) OR ("behavioural economics")).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((\"behavior economics\") OR (\"behavioral economic\"))) or (\"behavioural economics\"))".
• Removing quotes may allow a broader search: (((( behavior economics ) OR ( behavioral economic ))) or ( behavioural economics )).
• Adding a wildcard symbol may retrieve word variants: (((("behavior economics") OR ("behavioral economic"))) or ("behavioural economics"))*.