Im not sure if theirs one anime series I know that doesn't have nudity that features extreme violence as well, but if nudity or a few little explict scenes.
1. Elfen Lied (My favriote anime that offers enough of decepations, bloodspill, but also involves whole other diffrent extremes. Theres nudity and some suggestive scenes, but nothing too explict.)
2. Gantz ( I haven't watched it myself, but I heard its up to par with Elfen Lied. It might contain some sex scenes though.)
3. Berserk (A great fantasy anime that offers enough bloodspray here and there. Some specific scenes can be really disturbing.
Theres more like Fist of the North Star, Ninji Scroll, Kite, Angels Cop, Devilmans OVA and so on.