You can't filter your search by episode count, as far as I know.
But you can quickly browse the Korean ones using this link:
Korean dramas and drama specials:
http://mydramalist.com/browse/all?types[0]=68&type...Only Korean dramas:
http://mydramalist.com/browse/all?types[0]=68&sort...You have the number of episodes and the synopsis right there, so you can quickly skip the ones you are not interested in and just find what you look for.
You can also further refine the search by genres and year if you want (I only used the country criterion)...
I hope this helps a little.
