Perhaps you should try some spelling variations:
"digitalia ebook collection: con adicion." » "digitalia ebook collecting: con adicion.", "digitalia ebook collectors: con adicion.", "digitalia ecoin collections: con adicion.", "digitalia ebooks collection: con adicion."
"digitalia book collection: como mediador." » "digitalia book collecting: como mediador.", "digitalia book collectors: como mediador.", "digitalia coin collections: como mediador.", "digitalia book collection: como indicador.", "digitalia book collection: como mediacion.", "digitalia book collection: como medio."

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: (("digitalia ebook collection: con adicion.") or ("digitalia book collection: como mediador."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("digitalia ebook collection: con adicion.") OR ("digitalia book collection: como mediador.")).
• Removing quotes may allow a broader search: (( digitalia ebook collection: con adicion. ) or ( digitalia book collection: como mediador. )).
• Adding a wildcard symbol may retrieve word variants: (("digitalia ebook collection: con adicion.") or ("digitalia book collection: como mediador."))*.