Perhaps you should try some spelling variations:
"scale immigration rules." » "scale migration rules.", "scale irrigation rules.", "scale integration rules.", "scale immigration quotas.", "scale immigration law.", "scale immigration laws."
"can migration studies." » "main migration studies.", "von migration studies.", "urban migration studies."
"a migration studies." » "der 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 rules.") or ((("can migration studies.") or ("a migration studies."))))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("scale immigration rules.") OR ((("can migration studies.") OR ("a migration studies.")))).
• Removing quotes may allow a broader search: (( scale immigration rules. ) or ((( can migration studies. ) or ( a migration studies. )))).
• Adding a wildcard symbol may retrieve word variants: (("scale immigration rules.") or ((("can migration studies.") or ("a migration studies."))))*.