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