Perhaps you should try some spelling variations:
"ambulance" » "ambulanten", "ambulanter", "imbalance"
"ambulante" » "ambulanten"
"ambulantes" » "ambulantens", "ambulanten", "ambulanter", "ambulant"
"ambulantens" » "ambulantenns", "ambulanten", "ambulanter", "ambulances"

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: (("ambulance" OR "ambulante") OR ("ambulantes" OR "ambulantens")).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"ambulance\" or \"ambulante\") or (\"ambulantes\" OR \"ambulantens\"))".
• Removing quotes may allow a broader search: (( ambulance or ambulante ) or ( ambulantes OR ambulantens )).
• Adding a wildcard symbol may retrieve word variants: (("ambulance" or "ambulante") or ("ambulantes" OR "ambulantens"))*.