Perhaps you should try some spelling variations:
historia americana » historia mexicana, history american, history americas
historia mexican » historia mexicana, historia mexico, history mexican
lecturas de » lecturas del, lectura de, lectures de

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

• If you are trying to use Boolean operators, they must be ALL CAPS: lecturas de ((historia americana) OR (historia mexican)).
• Adding a wildcard symbol may retrieve word variants: lecturas de ((historia americana) or (historia mexican))*.