Perhaps you should try some spelling variations:
"literatura y del islam." » "literatura y el islam."
"literatura de si isaac." » "literatura de de isaac.", "literatura de _ isaac.", "literatura de c isaac.", "literatura de su isaac.", "literatura de mi isaac."
"literatura de fe isaac." » "literatura de de isaac.", "literatura de e isaac.", "literatura de _ isaac."

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: (((("literatura de si isaac.") OR ("literatura de fe isaac."))) OR ("literatura y del islam."))~.
• Removing quotes may allow a broader search: (((( literatura de si isaac. ) or ( literatura de fe isaac. ))) or ( literatura y del islam. ))~.
• Adding a wildcard symbol may retrieve word variants: (((("literatura de si isaac.") or ("literatura de fe isaac."))) or ("literatura y del islam."))*.