DO NOT add this as the URL for a bookmark:
— Jon Tennant (@Protohedgehog) June 10, 2018
javascript:location.hostname += '.sci-hub.tw'
Which when you click on a paywalled research article, automatically takes you to the @Sci_Hub version of it.
And DO NOT try this, see that it works wonderfully, and share it with others.
This suggests some interesting bookmarklet functionality.