You can add an arbitrary number of tabs to the entry editor. These will be present for all entry types.
You specify one tab on each line. The line should start with the name of the tab, followed by a colon (:), and the fields it should contain, separated by semicolons (;).
E.g.General:url;keywords;doi;pdf
Abstract:abstract;annote
which would give one tab named "General" containing the fields url, keywords, doi and pdf, and another tab named "Abstract" containing the fields abstract and annote.