Perhaps you should try some spelling variations:
"positives" » "positive", "positiven", "positivees", "positivenes", "positiones"
"positivism" » "positiveism", "positivenism", "positionism"
"positiv" » "positive", "positiven", "position"
"positivity" » "positiveity", "positivenity", "positionity"
"positively" » "positiveely", "positivenely", "positionely", "positive"

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: (("positivism" OR ("positives" OR "positiv")) OR ("positivity" OR "positively")).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"positivism\" or (\"positives\" OR \"positiv\")) or (\"positivity\" or \"positively\"))".
• Removing quotes may allow a broader search: (( positivism or ( positives OR positiv )) or ( positivity or positively )).
• Adding a wildcard symbol may retrieve word variants: (("positivism" or ("positives" OR "positiv")) or ("positivity" or "positively"))*.