Perhaps you should try some spelling variations:
"social compact models" » "social compact model", "social compact modeling", "social component models", "social contract models", "social impacts models", "social contracts models"
"social complex models" » "social complexity models"
"social impact model" » "social compact model", "social exact 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 impact model") OR ("social compact models"))) OR ("social complex models")).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((\"social impact model\") OR (\"social compact models\"))) or (\"social complex models\"))".
• Removing quotes may allow a broader search: (((( social impact model ) OR ( social compact models ))) or ( social complex models )).
• Adding a wildcard symbol may retrieve word variants: (((("social impact model") OR ("social compact models"))) or ("social complex models"))*.