Perhaps you should try some spelling variations:
"communicate diseases" » "communicable diseases", "communicated disease", "communicate disabled"
"complicated diseases" » "complex diseases", "mediated diseases", "complicated case"
"communicable disease" » "communicable 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 ((("complicated diseases") OR ("complicated cases"))))) OR ("communicable disease")).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((\"communicate diseases\") or (((\"complicated diseases\") OR (\"complicated cases\"))))) or (\"communicable disease\"))".
• Removing quotes may allow a broader search: (((( communicate diseases ) or ((( complicated diseases ) OR ( complicated cases ))))) or ( communicable disease )).
• Adding a wildcard symbol may retrieve word variants: (((("communicate diseases") or ((("complicated diseases") OR ("complicated cases"))))) or ("communicable disease"))*.