Updated & Corrected Ruling
I can find no rule anywhere that indicates that thrown weapons, specifically, do not get multiple attacks if the person doing the attacking has multiple attacks and uses the full attack combat action.
The only rule that would affect this AT ALL is the fact that you have to draw the weapon in order to throw it. Since this clearly does not impact archers, I am instituting the following ruling for small weapons:
Small throwing weapons can be hung in bandoliers, slings, or quivers (depending on their design) for easy grab-n-throw. This allows you to use your full attacks per round, as dictated by BAB, just like arrows for a bow. This has no impact on your ability to pull the weapon out in a grip firm enough to be suitable for melee combat - for that, take the Quick Draw feat.
Medium throwing weapons can be similarly hung, but still take a move equivalent action to draw, as a firm grip is required to throw them. You may take the Quick Draw feat to overcome this, allowing you your normal attacks per round.
Note: Where I say Small, read, "one size smaller than yourself", and where I say Medium, read, "any weapon you could concievably Quick Draw for melee".