Perhaps you should try some spelling variations:
"literatura y del islam." » "literatura y el islam."
"literatura de de isaac." » "literatura de den isaac.", "literatura de d_ isaac.", "literatura de dc isaac.", "literatura de fe isaac.", "literatura de di isaac."
"literatura de e isaac." » "literatura de en isaac.", "literatura de _ isaac.", "literatura de c isaac.", "literatura de el isaac.", "literatura de fe isaac."

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: (((("literatura de de isaac.") or ("literatura de e isaac."))) or ("literatura y del islam."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("literatura de de isaac.") OR ("literatura de e isaac."))) OR ("literatura y del islam.")).
• Removing quotes may allow a broader search: (((( literatura de de isaac. ) or ( literatura de e isaac. ))) or ( literatura y del islam. )).
• Adding a wildcard symbol may retrieve word variants: (((("literatura de de isaac.") or ("literatura de e isaac."))) or ("literatura y del islam."))*.