Perhaps you should try some spelling variations:
"immigrants agricultural autores mexicanos." » "migrant agricultural autores mexicanos.", "immigrants cultural autores mexicanos.", "immigrants agricultural actors mexicanos.", "immigrants agricultural laborers mexicanos.", "immigrants agricultural authors mexican."
"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."

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