Perhaps you should try some spelling variations:
"special effect model" » "special effects model", "spectral effects model", "social effects model", "special effect models", "special effects models"
"social effect model" » "social effects model", "societal effect model", "local effect model", "social effect models", "social effects models", "social enffect model"
"social et model" » "social en model", "social etats model", "social net model", "social set model", "social jet model", "social ent model"
"social e model" » "social en model", "social e modelli"

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