Perhaps you should try some spelling variations:
"societal effect model" » "societal effects model", "social effects model", "society effects model", "societal effect models", "societal effects models"
"special effect model" » "special effects model", "spectral effects model", "special respect model", "special effect models", "special effects models"
"social effect model" » "social effects model", "local effect model", "focal effect model", "social effect models", "social effects models"
"social exact model" » "social etats model", "social et model", "social email model"

Try widening your search to All Fields.

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: (("social exact model") OR ((((("social effect model") OR ("societal effect model"))) OR ("special effect model")))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"social exact model\") or (((((\"social effect model\") OR (\"societal effect model\"))) or (\"special effect model\"))))".
• Removing quotes may allow a broader search: (( social exact model ) or ((((( social effect model ) OR ( societal effect model ))) or ( special effect model )))).
• Adding a wildcard symbol may retrieve word variants: (("social exact model") or ((((("social effect model") OR ("societal effect model"))) or ("special effect model"))))*.