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