Perhaps you should try some spelling variations:
"serie detras de casos." » "serie letras de casos.", "serie lecturas de casos.", "serie retratos de casos.", "serie detras de caso."
"serie artes la clase." » "serie arte la clase.", "serie actas la clase.", "serie art la clase.", "serie cortes la clase.", "serie artes y clase."
"serie carta la clase." » "serie arte la clase.", "serie art la clase.", "serie cuarta la clase.", "serie carta a clase.", "serie marta la clase."

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: (((("serie artes la clase.") or ("serie carta la clase."))) or ("serie detras de casos."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("serie artes la clase.") OR ("serie carta la clase."))) OR ("serie detras de casos.")).
• Removing quotes may allow a broader search: (((( serie artes la clase. ) or ( serie carta la clase. ))) or ( serie detras de casos. )).
• Adding a wildcard symbol may retrieve word variants: (((("serie artes la clase.") or ("serie carta la clase."))) or ("serie detras de casos."))*.