Perhaps you should try some spelling variations:
"environmental activist" » "environmental activista", "environmental activism", "environmental activistas"
"environmental activists" » "environmental activistas", "environmental activisms", "environmental activistass", "environmental activista", "environmental activity"
"environment activist" » "environment activista", "environment activism", "environment activistas"

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 activists"))) OR ("environment activist"))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((\"environmental activist\") OR (\"environmental activists\"))) OR (\"environment activist\"))".
• Removing quotes may allow a broader search: (((( environmental activist ) OR ( environmental activists ))) OR ( environment activist )).
• Adding a wildcard symbol may retrieve word variants: (((("environmental activist") OR ("environmental activists"))) OR ("environment activist"))*.