The default filter for slow moving parts is ....-....-. This filter is a type of filter called a Regular Expression, also called regex for short. You are more familiar with glob filtering. Glob filtering primarily uses the asterisk, *. For example, 5010-*-, if the filter type was glob, which it is not, would yield results like 5010-0300-000, 5010-0700-001, and 5010-2500-013. The equivalent using regex as a filter is "5010-.*-". In this case, the dot (.) represents any character, i.e. a, b, c, etc. , A, B, C, etc., 0, 1, 2, etc.. The asterisk, *, after the dot means 0 or more of that 'any character'.
So then, if part nos. from a sw/sl BOM were 6415-2013-076 and 7302-0050-002, the ....-....-" filter would match numbers like 6415-2013-108, 6415-2013-118, 6415-2013-202, 7302-0050-000, 7302-0050-003, and 7302-0040-103-C from the sm BOM. On the other hand, if any of those dots were replaced, then the filter is altered accordingly. For example, 300.-01..- will match 3001-0100-001, 3005-0150-003, etc., and 3...-0050- will match 3001-0050-006 and 3214-0050-001-C.
Another useful filter is .........., i.e 10 dots. In this case, the first 10 characters are, again, 'any character'. The equivalent regex filter is .{10}. This means, 'any charater' 10 times. Both of these will match values like 9000-0006-000, 9263K297, A0013854-006, 3180-VMX05-000. ....-.*- will match 9000-0006-000 and 3180-VMX05-000.
The regex filtering examples introduced on this page are only the basics. For use in bomcheck, these basics are all you need to know. However if one wishes to delve into more complex examples, you can do a google search for "regex".