Perhaps you should try some spelling variations:
"mexicans zunited states social conditions." » "mexicans united states social conditions.", "mexican united states social conditions.", "americans united states social conditions."
"mexicana united states social conditions." » "mexicans united states social conditions.", "mexican united states social conditions.", "americans united states social conditions."

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

• Performing a fuzzy search may retrieve terms with similar spellings: (("mexicans zunited states social conditions.") or ("mexicana united states social conditions."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("mexicans zunited states social conditions.") OR ("mexicana united states social conditions.")).
• Removing quotes may allow a broader search: (( mexicans zunited states social conditions. ) or ( mexicana united states social conditions. )).
• Adding a wildcard symbol may retrieve word variants: (("mexicans zunited states social conditions.") or ("mexicana united states social conditions."))*.