Perhaps you should try some spelling variations:
"communicate discover" » "community discovery", "communicate disabled", "communications over"
"communicable disease" » "communicable diseases"
"complicated diseases" » "complicated cases", "complex diseases", "mediated diseases"

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: (((("communicate discover") OR ("communicable disease"))) OR ("complicated diseases")).
• Removing quotes may allow a broader search: (((( communicate discover ) or ( communicable disease ))) or ( complicated diseases )).
• Adding a wildcard symbol may retrieve word variants: (((("communicate discover") or ("communicable disease"))) or ("complicated diseases"))*.