Perhaps you should try some spelling variations:
"population ; espace economique" » "population ; espaces economiques", "population ; aspect economique"
"population ; space economical" » "population ; space economy", "population ; peace economic", "population ; socio economical"

You may be able to get more results by adjusting your search query.

• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"population ; space economical\") OR (\"population ; espace economique\"))".
• Removing quotes may allow a broader search: (( population ; space economical ) OR ( population ; espace economique )).
• Adding a wildcard symbol may retrieve word variants: (("population ; space economical") OR ("population ; espace economique"))*.