Perhaps you should try some spelling variations:
"immigrants agricultural laws mexico." » "migrant agricultural laws mexico.", "immigrants cultural laws mexico.", "immigrants agricultural laborers mexico.", "immigrants agricultural law mexico.", "immigrants agricultural class mexico.", "immigrants agricultural blacks mexico."
"migrantes agricultural labor mexico." » "migrant agricultural labor mexico.", "migrantes culturas labor mexico.", "migrantes agricultural laborers mexico.", "migrantes agricultural law mexico.", "migrantes agricultural actors mexico."

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: (("migrantes agricultural labor mexico.") or ("immigrants agricultural laws mexico."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("migrantes agricultural labor mexico.") OR ("immigrants agricultural laws mexico.")).
• Removing quotes may allow a broader search: (( migrantes agricultural labor mexico. ) or ( immigrants agricultural laws mexico. )).
• Adding a wildcard symbol may retrieve word variants: (("migrantes agricultural labor mexico.") or ("immigrants agricultural laws mexico."))*.