Perhaps you should try some spelling variations:
conference where » conference held (Expand Search), conference which (Expand Search)
conference sur » conference _ (Expand Search)
et conferences » _ conference (Expand Search), a conference (Expand Search)
xvie siecle » xvie siecles (Expand Search), xviiie siecle (Expand Search), xxe siecle (Expand Search)
where le » where _ (Expand Search)
sur le » sur la (Expand Search)
congress » kongress (Expand Search), congresses (Expand Search)

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

• Performing a fuzzy search may retrieve terms with similar spellings: (((( colloque, ((congres a) OR (congress _)) conference sur le xvie siecle ) or ( colloque, ((congres a) OR (congress _)) conference where le xvie siecle ))) or ( colloque, congres et conferences sur le xvie siecle ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((( colloque, ((congres a) OR (congress _)) conference sur le xvie siecle ) OR ( colloque, ((congres a) OR (congress _)) conference where le xvie siecle ))) OR ( colloque, congres et conferences sur le xvie siecle )).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(((( colloque, ((congres a) OR (congress _)) conference sur le xvie siecle ) or ( colloque, ((congres a) OR (congress _)) conference where le xvie siecle ))) or ( colloque, congres et conferences sur le xvie siecle ))".
• Adding a wildcard symbol may retrieve word variants: (((( colloque, ((congres a) OR (congress _)) conference sur le xvie siecle ) or ( colloque, ((congres a) OR (congress _)) conference where le xvie siecle ))) or ( colloque, congres et conferences sur le xvie siecle ))*.