Found a solution.
Still would be interesting to know if FileMaker has a similar command as excel's asterisk.
You can't use a wild card character like that except as an operator in find criteria specified while in find mode.
But there are a lot of text functions in FileMaker.
PatternCount and Position are two that can prove very useful when searching a field for specific subtext. The first counts the number of instances found and the second returns the position of the first character of the searched for text. Both return zero if the search string is not found.