Which screw for 45-timber - why is the unthreaded part of the screws so short?

[Tomtom79]

I'm planning to put up an interior wall and want to fasten a 45x95 standing on its edge to the floor joists so I would prefer a screw that is unthreaded 90-95mm. Does that exist?

Longer screws often don't have very long threads, instead having a longer unthreaded portion.

https://www.heco.se/sortiment/trainfastningar/traskruv-protect-4/hardad-traskruv-tft-protect-4.html

For example, a 160mm long one has 88mm unthreaded, if you drive it in a bit more, it's more than 90.