Perhaps you should try some spelling variations:
"complicated diseases" » "complex diseases", "mediated diseases"
"complicated cases" » "complicated acutes", "complicated chapters", "complicated griefs"
"complicated case" » "complicated acute", "complicated chapter", "complicated grief"

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 cases") OR ((("complicated diseases") OR ("complicated case"))))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"complicated cases\") or (((\"complicated diseases\") OR (\"complicated case\"))))*".
• Removing quotes may allow a broader search: (( complicated cases ) or ((( complicated diseases ) OR ( complicated case ))))*.