is there anything close to Sliders on TV right now?

The closest i can think of is Stargate SG1, Charlie Jade or Eureka.

Replying for Stargate (only one listed that I watched). Kind of the same. Enter a blue portal, appear in an alien world that kind of looks like earth with humans, face problems and challenges, escape back into the portal.

On SyFy or "on TV"? Fringe would have been the closest when you posted this. Eureka would have been vaguely relevant, due to the science aspect, but that's about it.

The Flash has alternate worlds now

Parallels. Almost exact same premise. They released a pilot a while ago but who knows if it'll get picked up