Any way to block search by certain key words

The search tap shows the searches my kids made.  But there is nothing to allow me to control whether such search key is allowed.  

 

How can I block certain key words search.

 

Another question is how can I apply the same set of restrictions on more than one account.  Say, I block a site in one of my kid's account, I want that same site blocked in other kid accounts as well.  Do I have to do the blocking on each account?