Perhaps you should try some spelling variations:
proceedings etc » proceedings 5th, proceedings 4th, proceedings 11th
proceedings 2nd » proceedings 2000, proceedings 2001, proceedings 2003
proceedings ec » proceedings 2, proceedings 1, proceedings 14

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

• If you are trying to use Boolean operators, they must be ALL CAPS: ((proceedings ec) OR (((proceedings etc) OR (proceedings 2nd)))) report.
• Adding a wildcard symbol may retrieve word variants: ((proceedings ec) or (((proceedings etc) or (proceedings 2nd)))) report*.