This question could seem dumb, but... is PS4 backwards compatible with some ps3 games?
Off course Skyrim on ps3 is surely not readable by ps4, otherwise there would not be a Skyrim SE. but with other games?
Sorry for bothering with an off topic-off forum question, but if someone could be so kind to answer me, it would be nice.

Nope not one PS3 disk, the only way to play PS3 games on the PS4 is to have a PS Now subscription.