Perhaps you should try some spelling variations:
"environmental activist" » "environment activist", "environmental activista", "environmental activists", "environmental activism"
"environmental activisma" » "environment activisma", "environmental activismo", "environmental activista", "environmental activism"
"environmental activity" » "environment activity"

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: (("environmental activist") OR ((("environmental activisma") OR ("environmental activity"))))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"environmental activist\") OR (((\"environmental activisma\") OR (\"environmental activity\"))))*".
• Removing quotes may allow a broader search: (( environmental activist ) OR ((( environmental activisma ) OR ( environmental activity ))))*.