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

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") OR ("economic interaction")))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"ergonomic interventions\") or (((\"economic intervention\") OR (\"economic interaction\"))))".
• Removing quotes may allow a broader search: (( ergonomic interventions ) or ((( economic intervention ) OR ( economic interaction )))).
• Adding a wildcard symbol may retrieve word variants: (("ergonomic interventions") or ((("economic intervention") OR ("economic interaction"))))*.