Question: Is it possible to deny or prevent or obstruct a network scan on the network where your computer is connected to?

Answer: 
If you don't want your pc to be scanned for open ports or available services, you can use a firewall that closes/stealths the necessary ports. Beware, certain ports wil always be open to be able to communicate with the network.
You can't without disconnecting from the network.

All the firewalls and IDS in the world can't stop it if someone knows what they are doing.