I assume that field is a custom one? I'm unfamiliar with it. Anyway here is what my search would be. Criteria: Type is Item Receipt, Main Line is False, Tax Line is False, Shipping Line is False. Then in results, have Item and then scroll to the bottom of the field dropdown, you should see field names with three dots at the end, so you want to click on

Item Fields...

then select the field name you want.