Search Various Document Servers

• OPUS Metasearch Engine
  Metasearch engine for digital academic publications
• BASE (Bielefeld Academic Search Engine)
  Multidisciplinary search engine for scientifically relevant web resources (created and developed by Bielefeld University Library)
• OAIster
  Metasearch engine for digital resources
• ScientificCommons
  Metasearch engine for electronic scientific publications that can be accessed for free