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 migrant irrigation schemes." » "support migration irrigation schemes.", "support migrant integration schemes.", "support micro irrigation schemes.", "support migrant irrigation scheme.", "support migrant irrigation systems.", "support migrants irrigation schemes.", "support grant irrigation schemes.", "supporting migrants 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: (("import data integration theories.") or ("support migrant irrigation schemes."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("import data integration theories.") OR ("support migrant irrigation schemes.")).
• Removing quotes may allow a broader search: (( import data integration theories. ) or ( support migrant irrigation schemes. )).
• Adding a wildcard symbol may retrieve word variants: (("import data integration theories.") or ("support migrant irrigation schemes."))*.