Perhaps you should try some spelling variations:
economic agent » economic agents, economic rents, economic aspects
recherche und » recherche en, recherche d'une, recherche prend
economic rent » economic rents, economic report, economic trends
studi per » studie der
studia ve » studie v, studia 4, studia a
studi e » studie 2, studi di, studie _

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((((studi e) or (studia ve))) or (studi per)) recherche und ((economic agent) OR (economic rent)) ;~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((((studi e) OR (studia ve))) OR (studi per)) recherche und ((economic agent) OR (economic rent)) ;.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((studi e) or (studia ve))) or (studi per)) recherche und ((economic agent) OR (economic rent)) ;".
• Adding a wildcard symbol may retrieve word variants: ((((studi e) or (studia ve))) or (studi per)) recherche und ((economic agent) OR (economic rent)) ;*.