Perhaps you should try some spelling variations:
"scale immigration status." » "scale migration status.", "scale irrigation status.", "scale integration status."
"trade migration studies." » "male migration studies.", "pre migration studies.", "re migration studies."
"can migration studies." » "main migration studies.", "von migration studies.", "urban migration studies."

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

• Performing a fuzzy search may retrieve terms with similar spellings: (("scale immigration status.") or ((("trade migration studies.") or ("can migration studies."))))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("scale immigration status.") OR ((("trade migration studies.") OR ("can migration studies.")))).
• Removing quotes may allow a broader search: (( scale immigration status. ) or ((( trade migration studies. ) or ( can migration studies. )))).
• Adding a wildcard symbol may retrieve word variants: (("scale immigration status.") or ((("trade migration studies.") or ("can migration studies."))))*.