Perhaps you should try some spelling variations:
"communicated diseases" » "communicated disease", "communicate disabled", "communicate discover"
"communicate diseases" » "communicated disease", "communicate disabled", "communicate discover"
"complicated diseases" » "complex diseases", "mediated diseases", "complicated case"

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