Perhaps you should try some spelling variations:
convenio de » convencion de (Expand Search)
"Convenio de La Haya de 1973" » "Convenio de La Haya de 1978" (Expand Search), "Convenio de La Haya de 1993" (Expand Search), "Convenio de La Haya de 1983" (Expand Search)
"Convenio de La Haya de 1979" » "Convenio de La Haya de 1978" (Expand Search), "Convenio de La Haya de 1999" (Expand Search)
haya » hay (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: (("Convenio de La Haya de 1973") OR ("Convenio de La Haya de 1979"))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"Convenio de La Haya de 1973\") OR (\"Convenio de La Haya de 1979\"))".
• Removing quotes may allow a broader search: (( Convenio de La Haya de 1973 ) OR ( Convenio de La Haya de 1979 )).
• Adding a wildcard symbol may retrieve word variants: (("Convenio de La Haya de 1973") OR ("Convenio de La Haya de 1979"))*.