Perhaps you should try some spelling variations:
communication conversion » communication conversation, communications convention, communication cohesion
dimensions derivation » dimensional variation, dimensions operations
conversion methods » conversion method, inversion methods, inversion method
dimensions vision » dimensions session, dimensional division, dimensional version

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

• Performing a fuzzy search may retrieve terms with similar spellings: communication conversion methods ((dimensions derivation) or (dimensions vision)) level~.
• If you are trying to use Boolean operators, they must be ALL CAPS: communication conversion methods ((dimensions derivation) OR (dimensions vision)) level.
• Adding a wildcard symbol may retrieve word variants: communication conversion methods ((dimensions derivation) or (dimensions vision)) level*.