Perhaps you should try some spelling variations:
"complicated diseases" » "complicated cases", "complex diseases", "mediated diseases"
"communicate disabled" » "communicate discover", "communicate listen", "communicate defined"
"communicated disease" » "communicable disease", "communicate state", "communicated vision"

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