For all runways I've known or seen, they're numbered on both sides, with the number on the opposite direction differ by 18.
Are there runways that are numbered only on one side? I.e. due to certain constrains, the runway can only be used in one direction and never the other.
EDIT: I'm looking for runways where the aircraft is always pointing at the same direction. E.g. only runway 9 is available, you can never use runway 27 for whatever reason.
A runway that is blocked on one end will still have two numbers, since you'd land at one direction and takeoff the other.