In its default setting, desLibris presents all titles which have been made available by publishers on the site without filtering.
On the public site, viewers only see previews of public documents and books.
Viewers coming to desLibris though an authenticated library address, on the other hand, have access to full text views of the books and/or documents to which the library has subscribed or which it has purchased, but also previews of those not included in the active subscriptions or library holdings.
Users may restrict results (remove those not available in full text) with the filters/facets panel in the Search window.
But library administrators may also pre-determine (hide) results from their users with the "Customized Search Settings" option on the "Settings and Content Options" tab in Administration module.
Clicking on this button will present a search window on which you may tailor results. In the example below, checking the highlighted boxes would restrict results to only Books where the full text is available for fulltext use (either by reason of a subscription or purchase.) Preview titles will therefore not be presented to users.