Perhaps you should try some spelling variations:
2c reliability » 2 reliability, 20 reliability, 24 reliability
9 reliability » 3 reliability, 5 reliability, 2 reliability
2_ safety » 2 safety, 22 safety, 25 safety
23 safety » 3 safety, 2 safety, 13 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%((2c reliability) OR (9 reliability))%((((2_ safety) OR (23 safety))) OR (_ safety)) AND risk%22.
• The words AND, OR and NOT may confuse the search; try adding quotes: "%quality control%((2c reliability) or (9 reliability))%((((2_ safety) OR (23 safety))) or (_ safety)) and risk%22".
• Adding a wildcard symbol may retrieve word variants: %quality control%((2c reliability) or (9 reliability))%((((2_ safety) OR (23 safety))) or (_ safety)) and risk%22*.