Perhaps you should try some spelling variations:
_quality control » quality control, byquality control, quality controls
22 safety » 12 safety, 5 safety, 4 safety
2 safety » 5 safety, 4 safety
3 safety » 5 safety, 4 safety

Try widening your search to All Fields.

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: %_quality control%((((5 reliability) OR (3 reliability))) OR (2 reliability))%((((22 safety) OR (2 safety))) OR (3 safety)) AND risk%22.
• The words AND, OR and NOT may confuse the search; try adding quotes: "%_quality control%((((5 reliability) OR (3 reliability))) or (2 reliability))%((((22 safety) or (2 safety))) or (3 safety)) and risk%22".
• Adding a wildcard symbol may retrieve word variants: %_quality control%((((5 reliability) OR (3 reliability))) or (2 reliability))%((((22 safety) or (2 safety))) or (3 safety)) and risk%22*.