You can access the MARC Expert Search by clicking on the Expert Search tab on the Advanced Search screen.
If you are familiar with the MARC standard, you may search by specific MARC tags in the Expert Search.
Enter the three-digit tag number, the subfield (if relevant), and the value or text that corresponds to the tag. For example, to search by publisher name, enter 264 b Random House.
The value in the MARC record must exactly match the value you enter as your search term or it will not be included in the results.