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