Perhaps you should try some spelling variations:
workers volunteers » worker volunteer, horse volunteers, older volunteers
infants treatment » implants treatment, its treatment, effects treatment
infants regiment » infantry regiment, its regiment
new workers » new yorker, new markers, line workers

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

• The words AND, OR and NOT may confuse the search; try adding quotes: "7th new workers volunteers ((infants regiment) OR (infants treatment))".
• Adding a wildcard symbol may retrieve word variants: 7th new workers volunteers ((infants regiment) OR (infants treatment))*.