Perhaps you should try some spelling variations:
"ergonomic interventions" » "robotic interventions", "endoscopic interventions", "genetic interventions"
"economic intervention" » "economic interaction", "economic interpretation", "economic integration"

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: (("ergonomic interventions") OR ("economic intervention")).
• Removing quotes may allow a broader search: (( ergonomic interventions ) or ( economic intervention )).
• Adding a wildcard symbol may retrieve word variants: (("ergonomic interventions") or ("economic intervention"))*.