Perhaps you should try some spelling variations:
"export trade integration theories." » "export trade integration theorems.", "export trade integrationstheorie 2.", "export trade integration theory.", "export taxes integration theories.", "export base integration theories.", "export tax integration theories."
"support grid irrigation schemes." » "support grid irrigation scheme.", "support grid irrigation systems.", "support grain irrigation schemes.", "support drip irrigation schemes.", "support gray irrigation schemes.", "support agri irrigation schemes.", "support grant irrigation schemes.", "support group irrigation schemes."

Try widening your search to All Fields.

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

• Performing a fuzzy search may retrieve terms with similar spellings: (("support grid irrigation schemes.") or ("export trade integration theories."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("support grid irrigation schemes.") OR ("export trade integration theories.")).
• Removing quotes may allow a broader search: (( support grid irrigation schemes. ) or ( export trade integration theories. )).
• Adding a wildcard symbol may retrieve word variants: (("support grid irrigation schemes.") or ("export trade integration theories."))*.