Perhaps you should try some spelling variations:
"research professional" » "researching professional", "resources professional", "research progressional", "research professionalsal", "research progressionsal"
"research profession" » "research progression", "research professionals", "research progressions"
"health professional" » "health professionals", "health professions", "healthcare professionals"
"research professor" » "research process", "research processes", "research prozess"

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: (("research professor") OR ((("research profession") OR ((("research professional") OR ("health professional")))))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"research professor\") or (((\"research profession\") or (((\"research professional\") OR (\"health professional\"))))))".
• Removing quotes may allow a broader search: (( research professor ) or ((( research profession ) or ((( research professional ) OR ( health professional )))))).
• Adding a wildcard symbol may retrieve word variants: (("research professor") or ((("research profession") or ((("research professional") OR ("health professional"))))))*.