Perhaps you should try some spelling variations:
"serie lecturas de clacsos." » "serie letras de clacsos.", "serie lectura de clacsos.", "serie lecturas de clacso.", "serie lecturas de casos.", "serie lecturas de clases."
"serie actas la clase." » "serie letras la clase.", "serie fichas la clase.", "serie actis la clase.", "serie actos la clase.", "serie lacteas la 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 actas la clase.") or ("serie carta la clase."))) or ("serie lecturas de clacsos."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("serie actas la clase.") OR ("serie carta la clase."))) OR ("serie lecturas de clacsos.")).
• Removing quotes may allow a broader search: (((( serie actas la clase. ) or ( serie carta la clase. ))) or ( serie lecturas de clacsos. )).
• Adding a wildcard symbol may retrieve word variants: (((("serie actas la clase.") or ("serie carta la clase."))) or ("serie lecturas de clacsos."))*.