Q:

Are there runways that are numbered only on one side?

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.

A:

Yes, there are runways numbered on only one side. 
For example, the third runway in the Frankfurt Airport (18, Runway west) is used only for takeoffs (to the south) and not for landings. Hence only number 18 is used. The other runways are used for both takeoffs and landings and are numbered 07C/25C, 07R/25L and 07L/25R.
Thomas Römer/OpenStreetMap data [CC BY-SA 2.0], via Wikimedia Commons
This restriction is due to the fact that it will interfere with the traffic in other runways.
Number 36 is not painted.

