In MacBook Pro, how to keep selected word(s) highlighted on the screen continuously whilst reading and till finish?

I do a lot of reading (or research) on webpages using Safari. I use "edit - find" to locate the same keyword as it appears throughout the passages. This helps me to fast read and get to the relevant contents quickly. However, I find that there is no sure way of keeping all those highlighted positions shown continuously till finish. Whenever the highlighting disappears, I have to restart the "edit-find" process again and which of course is rather annoying.

Could someone advise a better way of handling it? And, better still, what about tackling multiple keywords at the same time? Thanks.