Perhaps you should try some spelling variations:
historia americana » historia mexicana, history american, history americas
lectures diel » lectures field, lectures de, lectures data
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: ((lectures diel) OR (lettera del)) historia americana.
• Adding a wildcard symbol may retrieve word variants: ((lectures diel) or (lettera del)) historia americana*.