Just keep searching the anomalies. Anomalies will actually respawn with new artifacts after a while, so go back and check them every once in a while. Keep searching and eventually you'll get the radiation reduction artifacts, along with the weight increase artifacts. Until you get the rad reduction ones, you pretty much can't use any of the artifacts. In Jupiter there's a quest line for the Scientists that has you placing sensors in a whole bunch of anomolies. Once you've done that, you can see if new artifacts have spawned in the anomolies just by looking at your PDA map, which is nice.
Be aware that the artifacts you find tend to get more powerful the deeper you go into the zone. You'll find more powerful artifacts in Jupiter than in Zaton, and more powerful artifacts in Pripyat than in Jupiter.
Bookmarks