In the beginning of the game, I sacrificed some karma to get a repair +10 from a magazine (I stole it). But after only like 10 seconds, I got a message saying that its effect has worn off. Are all magazines temporary now, or is there only a selection magazines with sustained effects?
 
This kind of disappointed me.

Yes, but i found magazine that only give +3 stats without saying any effects in the info bar, maybe those are perm?

I believe there are magazines and also the books from Fallout 3.  Hard to tell them apart in your inventory though.

The temporary skill boosters are the ones that show for example +10 science etc. The permanent skill boosters are ones that don't show any stats.

Yeah I was wondering about that...

Wish I knew that before I used the magazine.

What I've heard there are Magazines that gives you a temporary skill increase and there are books that gives you a permanent increase in skill.

Just started playing yesterday, and noticed the same thing.   I guess it's cool that they mix it up a bit.