Search 'problems'

I have certain columns set as dropdown menus.
I can use Advanced search with no problems

but if I type part of the dropdown in a simple search, the search gives no results
for example
my drop down menu has the following 3 values:
ONa(RN)

ONA(RPN)

Registered Nurse
If I use simple search with
any fiels, contains RN
I get NO results
If i use adnvaced search and use the drop downed selections NO problems -- I find everything I need.

however if I TYPE inside part of the value get NO results