Perhaps you should try some spelling variations:
historia americana » historia mexicana, history american, history americas
lecturas del » lectura del, lectures diel, lectura de
lettera del » lettura del, lettera di, lettura dei

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 del) OR (lettera del)) historia americana.
• Adding a wildcard symbol may retrieve word variants: ((lecturas del) or (lettera del)) historia americana*.