Perhaps you should try some spelling variations:
agricultural subsidies » agricultural residues
agricultural policies » agricultural policy, agricultural products, agricultural commodities
agricultural sources » agricultural resources, agricultural surveys, agricultural survey
structural studies » cultural studies

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: %((structural studies) OR (((((agricultural subsidies) OR (agricultural policies))) OR (agricultural sources)))) AND transdisciplinarity in education%22.
• The words AND, OR and NOT may confuse the search; try adding quotes: "%((structural studies) or (((((agricultural subsidies) OR (agricultural policies))) or (agricultural sources)))) and transdisciplinarity in education%22".
• Adding a wildcard symbol may retrieve word variants: %((structural studies) or (((((agricultural subsidies) OR (agricultural policies))) or (agricultural sources)))) and transdisciplinarity in education%22*.