Perhaps you should try some spelling variations:
"import data integration theories." » "import data integration theorems.", "import data integrationstheorie 2.", "import data integration theory.", "import data integrity theories.", "import duty 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."

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 ("import data integration theories."))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"support grid irrigation schemes.\") OR (\"import data integration theories.\"))".
• Removing quotes may allow a broader search: (( support grid irrigation schemes. ) OR ( import data integration theories. )).
• Adding a wildcard symbol may retrieve word variants: (("support grid irrigation schemes.") OR ("import data integration theories."))*.