Perhaps you should try some spelling variations:
_quality control » quality control, byquality control, quality controls
4 reliability » 3 reliability, 2 reliability
5 reliability » 3 reliability
2c safety » 2 safety, 22 safety, 23 safety
3 safety » 5 safety
4 safety » 5 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%((4 reliability) OR (5 reliability))%((2c safety) OR (((3 safety) OR (4 safety)))) AND risk%22.
• The words AND, OR and NOT may confuse the search; try adding quotes: "%_quality control%((4 reliability) or (5 reliability))%((2c safety) or (((3 safety) OR (4 safety)))) and risk%22".
• Adding a wildcard symbol may retrieve word variants: %_quality control%((4 reliability) or (5 reliability))%((2c safety) or (((3 safety) OR (4 safety)))) and risk%22*.