It's not like sci-hub hosted anything, AFAIK. Didn't it just circumvent paywalls?
If I'm right (and fucking Elsevier & co. didn't patch the security holes) it should still work, but the sci-hub proxy sites are most likely defunct.
As those in the know can probably tell, I didn't keep up with the whole takedown, but I do miss that easy access to research articles.
No pretty sure it was an actual pdf database. I think there are mirrors that allow you to access all of Alexandra's wonderful work. But nothing new is being added due to legal injunctions.
Such a shame. Alexandra has added more to scientific advancement than most scientists themselves. Removing the barriers to shared scientific data is one of the greatest piracy feats ever accomplished.