There are options behind the FIND field that you can use to narrow down your search. The same options are available in the TEXT filter when creating a custom TAB on the dashboard. You can also use the so-called wildcard.
Note that the requirement search includes partial matches (i.e. EN 60335-2-33 matches with EN 60335-2-33:2013 and EN 60335-2-33:2016
Showing only files with an article number ending with „6“ - FIND article:*6
Showing only files with the tag „UK“ - FIND tag:“UK“