Perhaps you should try some spelling variations:
"conferencia ministeriales." » "conferencia ministerial.", "conferencias magistrales.", "conferencia magistral."
"conferencia magistrales." » "conferencias magistrales.", "conferencia magistral."
"conferencia nacional." » "conciencia nacional.", "conferencia internacional.", "confederacion nacional."

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: (((("conferencia magistrales.") or ("conferencia ministeriales."))) or ("conferencia nacional."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("conferencia magistrales.") OR ("conferencia ministeriales."))) OR ("conferencia nacional.")).
• Removing quotes may allow a broader search: (((( conferencia magistrales. ) or ( conferencia ministeriales. ))) or ( conferencia nacional. )).
• Adding a wildcard symbol may retrieve word variants: (((("conferencia magistrales.") or ("conferencia ministeriales."))) or ("conferencia nacional."))*.