Currently there are four search types:

Basic Search
Using Title and Author searching is likely to be adequate for most searches.

Advanced Search

A more advanced search form.

ISBN/ISSN Batch Search
This search does multiple ISBN and ISSN searches for each connection.

ISBNs can also be loaded from a text file.

Prefix Query Format (PQF)

Simple form to help create PQF queries.

The Edit button opens up the "Search Attribute Editor".

See YAZ documentation from Index Data for more information about Prefix Query Format.

Search Attribute Editor
The Search Attribute Editor helps to create PQF queries without having to look up the values.

Selecting the search type buttons on the basic and advanced search screens will open the attribute editor. The Attribute Editor currently only supports Bib-1.

Warning: The are a lot of options here which most Z39.50 servers will not support.