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