Perhaps you should try some spelling variations:
"activa de congreso." » "activa al congreso." (Expand Search), "activa i congreso." (Expand Search), "activa ii congreso." (Expand Search), "activas de congreso." (Expand Search), "activa en congreso." (Expand Search), "activa y congreso." (Expand Search)
"activa el congreso." » "activa del congreso." (Expand Search), "activar el congreso." (Expand Search), "activa en congreso." (Expand Search)
"acta del congreso." » "actas del congreso." (Expand Search), "acta de congreso." (Expand Search), "carta del congreso." (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: (("acta del congreso.") OR ((("activa de congreso.") OR ("activa el congreso."))))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"acta del congreso.\") OR (((\"activa de congreso.\") OR (\"activa el congreso.\"))))".
• Removing quotes may allow a broader search: (( acta del congreso. ) OR ((( activa de congreso. ) OR ( activa el congreso. )))).
• Adding a wildcard symbol may retrieve word variants: (("acta del congreso.") OR ((("activa de congreso.") OR ("activa el congreso."))))*.