Articles+ is a mega-index hosted by Primo developer Ex Libris. It contains more than one billion datasets from external sources. Those sources include publisher data, subject databases and subject portals as well as open-access data (compare List of providers in Primo mega-index).
♥ Hint: You can customize ranking rules in Articles+.
The basic result set is limited to resources listed in Article+ for which full texts are accessible. Freie Universität members and users at Freie Universität libraries have access to licensed e-resources.
♥ Hint: Check the "Expand My Results" box if you want results to be included for which full texts are not accessible. The expanded result list may contain titles that exist in printed editions in the Freie Universität library system or that can be procured from other libraries through interlibrary loan (compare: Information about Interlibrary Loan).
Articles+ is constantly being added to. However, sources relevant for your project may be not yet be included in the mega-index. Therefore, you should use the selection of databases provided by Freie Universität Berlin in addition to Primo. Another recommendation for your literature search is Google Scholar.