The padlock icons indicate the level of free public access to each resource in the database list:
=Content is open access (OA) or otherwise freely accessible. Some sites may require a free personal account.
=Content is mainly open access (OA). Some, usually older, content may be restricted to Illinois Tech or paywalled.
=Free to search, but content is likely to be paywalled or restricted to Illinois Tech students, faculty, or staff.
=Access is restricted to Illinois Tech students, faculty, and staff.