BASE is one of the world's most voluminous search engines especially for academic web resources. It provides more than 150 million documents from more than 7,000 Sources. You can access the full texts of about 60% of the indexed documents for free (Open Access). BASE is operated by Bielefeld University Library.

BASE is indexing the metadata of all kinds of academically relevant resources – journals, institutional repositories; digital collections etc.

In comparison to commercial search engines, BASE is characterized by the following features:

• Sources are indexed only after check by qualified personnel of Bielefeld University Library
• Only document servers and journals that comply with the specific requirements of academic quality and relevance are included
• A data resources inventory provides transparency in the searches
• Discloses web resources of the "Deep Web", which are ignored by commercial search engines or get lost in the vast quantity of hits
• Correction, normalization and enrichment of metadata by means of automated methods
• Mulitlingual search (find search terms in more than 20 translated languages)
• The display of search results includes precise bibliographic data
• Display of access and terms of re-use for a document
• Several options for sorting the result list (by author, title, date)
• "Refine your search result" options (by author, subject, DDC, year of publication, content provider, language, document type, access and terms of re-use)
• Browsing by DDC (Dewey Decimal Classification), document type, access and terms of re-use / licence.

To access BASE search engine please follow this link: https://www.base-search.net