No, When you fight a pokemon who has an element that is weak to yours, if it is stronger, it will still crush you. The screen, however will say that it is not a very effective attack. Like a Lv.10 Charmander vs. a level 2 Squirtle. It's attacks won't be ass effective, but will knock the Squirtle on his ass.
agh yesterday it says "seems to have some effect", today says "it's not very effective" D:, so i'm still thinking that "seems to have some effect it's the way that japaneses says it's NOT very eff.." (not super)
Larvitar used Rock Throw!
It's not very effective.