Perhaps you should try some spelling variations:
22quality control » quality control, byquality control, forquality control
_quality control » quality control, byquality control, quality controls
29 reliability » 2 reliability, 9 reliability, 2.6 reliability
24 reliability » 2.4 reliability, 2 reliability, 4 reliability
23 safety » 3 safety, 13 safety, 22 safety
2 safety » _ safety, a 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: %((22quality control) OR (_quality control))%((29 reliability) OR (24 reliability))%((23 safety) OR (2 safety)) AND risk%22.
• The words AND, OR and NOT may confuse the search; try adding quotes: "%((22quality control) or (_quality control))%((29 reliability) OR (24 reliability))%((23 safety) or (2 safety)) and risk%22".
• Adding a wildcard symbol may retrieve word variants: %((22quality control) or (_quality control))%((29 reliability) OR (24 reliability))%((23 safety) or (2 safety)) and risk%22*.