Perhaps you should try some spelling variations:
communication communicative » communication communication, communication communicating, communication communicate
communicative functions » communication foundations
extention databases » extending databases, expression databases, prevention databases
expression datasets » expression data

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

• Performing a fuzzy search may retrieve terms with similar spellings: communication communicative functions ((extention databases) or (expression datasets)) bncod~.
• If you are trying to use Boolean operators, they must be ALL CAPS: communication communicative functions ((extention databases) OR (expression datasets)) bncod.
• Adding a wildcard symbol may retrieve word variants: communication communicative functions ((extention databases) or (expression datasets)) bncod*.