Perhaps you should try some spelling variations:
"communicate diseases" » "communicable diseases", "communicated disease", "communicate disabled"
"complicated diseases" » "complicated cases", "complex diseases", "mediated diseases"
"communicable disease" » "communicable 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 diseases") OR ("complicated diseases"))) OR ("communicable disease")).
• Removing quotes may allow a broader search: (((( communicate diseases ) or ( complicated diseases ))) or ( communicable disease )).
• Adding a wildcard symbol may retrieve word variants: (((("communicate diseases") or ("complicated diseases"))) or ("communicable disease"))*.