The library portal Primo is the central search interface for searching and accessing local and outside resources, such as books, e-books, journal articles etc.; the Primo mega-index contains nearly one billion datasets.
The mega-index covers mainly English-language sources. A total of about 55,000 journals from more than 50 providers are indexed (see List of actve Ressources in the Primo megaindex (pdf-file)).
Primo functionalities include requesting, reserving, and managing user-accounts. User accounts show loaned items, requests, fees, and loan periods including renewal options if possible.
Be sure to consider the selection of databases provided by the Freie Universität Berlin. Depending on subject area and language, a comprehensive literature and information search should comprise (subject) databases in addition to Primo, in order to find sources beyond the contents of the Primo mega-index.