All terrier breeds have a stubborn streak; it is part of their personality as a hunting dog that has to defend itself against rats and other vermin. The terrier's tenacity and independence is famous and while the Cesky is not as stubborn and headstrong as other terrier breeds, they will have their moments.
The key to working with stubborn behavior is to make the dog think that he or she is doing what it wants to do, rather than making it a power struggle between the owner and the dog. Stubbornness it terriers is often because the terrier is already in one activity and doesn't want to switch to another at this particular point in time. It is also because they have been bred to be able to focus and track, something that requires the ability to block out distractions. In essence many of what owners call stubborn behaviors in more typical modern settings are the ideal characteristics the terriers just a few decades before were highly valued for.
The Cesky terrier was designed to be a ratter, but it did not inherit all the stubbornness that some of its close relatives in the terrier group posses. To help your Cesky through challenges with paying attention and obeying commands use small, healthy food rewards and lots of praise and attention. If you see that the dog is highly engaged in another activity, make sure you have his or her full attention before you issue a command, or you are likely to be ignored as the dog is elsewhere focused. A signal such as calling the dog's name is often a good tool to get them to look at you and see that you have a treat, making them much more likely to respond.
A stubborn dog that is simply not attending because he or she knows it is possible to get away with ignoring needs to go back to some of the basics of training. A NILF type training program is ideal for these dogs. NILF, sometimes written as NILIF, stands for Nothing In Life Is Free. Your dog will have to follow commands to get anything and everything he or she wants including food, going for a walk, playing with toys or getting your attention. With just a few short weeks of requiring the dog to do what he or she is told before they get what they want typically stubborn behavior is fully eliminated or at least greatly decreased. With NILF there is no punishment component, the dog is simply given a command and then only provided the reward when they are following the command at the appropriate time. For example, if you call the dog to come inside and he or she ignores you, close the door and wait 10-15 minutes. If the dog comes to the door and wants to get in, don't respond, but go to the door and repeat the command when the dog has walked away. If they return on command they can come in, if not repeat the process. Very quickly the dog will learn that following commands the first time is much more effective for them.