The option for 'Search Doll Profiles only' will be ticked by default.
If you are viewing a size category, the options for 'Search this category only' will also be ticked by default. Be sure to untick this option if you want to search all doll profiles.
You can do a more specific search by clicking the More button.
Click the Search Doll Profiles tab and then click Advanced Field Search.
This will let you search for specific information such as maker, head sculpt or faceup artist.