Perhaps you should try some spelling variations:
"communicate delegate" » "communicate climate", "communicate create", "communicate educate"
"communicated disease" » "communicate state", "communicated vision"
"complicated diseases" » "complicated cases", "complex diseases", "mediated diseases"
"communicate disease" » "community disease", "complicate disease", "communicate disabled"

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 ((("communicable disease") OR ((((("communicate disease") OR ("communicate delegate"))) OR ((("communicated disease") OR ("complicated diseases")))))))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"communicable diseases\") or (((\"communicable disease\") or (((((\"communicate disease\") OR (\"communicate delegate\"))) or (((\"communicated disease\") or (\"complicated diseases\"))))))))".
• Removing quotes may allow a broader search: (( communicable diseases ) or ((( communicable disease ) or ((((( communicate disease ) OR ( communicate delegate ))) or ((( communicated disease ) or ( complicated diseases )))))))).
• Adding a wildcard symbol may retrieve word variants: (("communicable diseases") or ((("communicable disease") or ((((("communicate disease") OR ("communicate delegate"))) or ((("communicated disease") or ("complicated diseases"))))))))*.