Pine wood flooring

[Joanie M]

I have an old house built in about 1955. The wood floors are made of a soft pine instead of hardwood. We've refinished them two or three times since we moved in 11 years ago. I'm needing to refinish them again and do some repair work. Does anyone know of anything stronger than polyeurothane that we can put on the floors to keep them from getting scratched, marked and dented like soft floors do????
Thanks,
Joanie