Perhaps you should try some spelling variations:
"disponibilidad y operatividad" » "disponibilidad de operatividad" (Expand Search), "responsabilidad y operatividad" (Expand Search), "visibilidad y operatividad" (Expand Search), "disponibilidad la operatividad" (Expand Search), "disponibilidad y creatividad" (Expand Search), "disponibilidad e hiperactividad" (Expand Search)
"sostenibilidad y operatividad" » "sostenibilidad de operatividad" (Expand Search), "y sostenibilidad operatividad" (Expand Search), "sostenibilidad la operatividad" (Expand Search), "sostenibilidad y creatividad" (Expand Search), "sostenibilidad e hiperactividad" (Expand Search)

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: (("disponibilidad y operatividad") OR ("sostenibilidad y operatividad"))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"disponibilidad y operatividad\") OR (\"sostenibilidad y operatividad\"))".
• Removing quotes may allow a broader search: (( disponibilidad y operatividad ) OR ( sostenibilidad y operatividad )).
• Adding a wildcard symbol may retrieve word variants: (("disponibilidad y operatividad") OR ("sostenibilidad y operatividad"))*.