A pattern can be setup made up on numbers [N], letters [L], vowels [V], consonants [C], hyphens [-] or any character [*].
If the pattern is an Exact Pattern, then the number of characters in the domain are the same number of characters in a pattern, i.e an exact pattern of [C][V][C][V] will find all domains that are four character long and match the pattern.
If the pattern is a Match Pattern, then the domain can have any number of characters as long as the pattern in matched in the domain name, i.e a match pattern of [C][V][C][V] will find all domains that match the pattern.
[C][V][C][V] Exact Pattern will show only domains that are four letter long and have the CVCV pattern - e.g. fifa.com, hulu.com, gogo.net
[C][V][C][V] Match Pattern will show any domains that contain the CVCV pattern - e.g. artfifa.com, hulucrafts.co.uk, gogodomains.com
[-][-] Match Pattern will show all domains that have two consecutive hyphens in them - e.g. magic--design.com, reservations--online.com
If you want to find domain names like google that can be used as a verb use the same pattern as google uses [C][V][V][C][C][V] or for yahoo use [L][V][C][V][V]