The site allows viewing stories by tag, and accepts a list of tags. Eg, https://lobste.rs/t/elixir,erlang will show all stories that have either of those tags.

However, any story that has more than one of those tags will be listed multiple times. In this screenshot from https://lobste.rs/t/elixir,erlang,browsers,compilers you can see that a story with two of the requested tags appears twice and a story with all four appears four times.