OpenVPMS allows the use of the 'wildcards' *, % and _ (underscore). Both * and % mean any number of characters, while _ means one character.
Thus a*b and a%b will find everything starting with 'a' following by zero or more characters, then a 'b'. There is also an implicit * added at the end of what you enter.
Hence a*b will find Abbie, Abe, Amber, and Annabelle. Note that the case you use does not matter, ie A*B will find the same names.
Using sm_th will find Smith and Smyth but not Smooth.
Note that since an implicit * is added to what you enter, leaving the Search field empty is equivalent to entering * and this will find all records.