Perhaps you should try some spelling variations:
"special effect model" » "special effects model", "spectral effects model", "special event model", "special effects models", "special effective model", "special object model"
"social effects model" » "special effects model", "social aspects model", "societal effects model", "local effects model", "focal effects model", "social effects models"
"social effect models" » "societal effect models", "local effect models", "focal effect models", "social effects modelss", "social effective models", "social object models"
"focal effects model" » "focal effects models", "local effects model", "focal effect model", "vocal effects model"
"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 ((((("special effect model") OR ("social effect models"))) OR ((("social effects model") OR ("focal effects model")))))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"social exact model\") or (((((\"special effect model\") or (\"social effect models\"))) or (((\"social effects model\") OR (\"focal effects model\"))))))".
• Removing quotes may allow a broader search: (( social exact model ) or ((((( special effect model ) or ( social effect models ))) or ((( social effects model ) OR ( focal effects model )))))).
• Adding a wildcard symbol may retrieve word variants: (("social exact model") or ((((("special effect model") or ("social effect models"))) or ((("social effects model") OR ("focal effects model"))))))*.