BASE is an essential tool for researchers. From the website: "BASE is one of the world's most voluminous search engines especially for academic open access web resources. BASE is operated by Bielefeld University Library. As the open access movement grows and prospers, more and more repository servers come into being which use the "Open Archives Initiative Protocol for Metadata Harvesting" (OAI-PMH) for providing their contents. BASE collects, normalises, and indexes these data. BASE is a registered OAI service provider and contributed to the European project "Digital Repository Infrastructure Vision for European Research" (DRIVER) which was successfully completed at the end of 2009. In comparison to commercial search engines, BASE is characterised by the following features:

• Intellectually selected resources
• Only document servers that comply with the specific requirementsof 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.
• The display of search results includes precise bibliographic data
• Several options for sorting the result list
• "Refine your search result" options (authors, subject headings, year, resources and language)
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For the results of a standard query with the word "Yiddish" see this page.