Perhaps you should try some spelling variations:
social exact » social effect, social etats, social et
etats model » etas model, beats model, seats model
hats model » charts model, habits model, shafts model
rats model » rat model, rate model, ratio model

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 ((((etats model) OR (hats model))) OR (rats model)) )).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( social exact model ) or ( social ((((etats model) OR (hats model))) or (rats model)) ))".
• Adding a wildcard symbol may retrieve word variants: (( social exact model ) or ( social ((((etats model) OR (hats model))) or (rats model)) ))*.