Perhaps you should try some spelling variations:
"environmental activist" » "environment activist", "environmental activista", "environmental activism", "environmental activistas"
"environmental activists" » "environment activists", "environmental activistas", "environmental activisms", "environmental activistass", "environmental activista", "environmental activismo"
"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 activists"))) OR ("environmental activity"))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((\"environmental activist\") OR (\"environmental activists\"))) OR (\"environmental activity\"))".
• Removing quotes may allow a broader search: (((( environmental activist ) OR ( environmental activists ))) OR ( environmental activity )).
• Adding a wildcard symbol may retrieve word variants: (((("environmental activist") OR ("environmental activists"))) OR ("environmental activity"))*.