Open Access Search Engines

It is necessary to compile available search engines at one place specifically designed for open access resources. Some of the important search engines are listed below:

1. Google Scholar (https://scholar.google.co.in/) - Launched in 2004 it is a search engine that indexes the full text or metadata of scholarly literature across an array of publishing formats and disciplines especially scholarly literature. It indexes different types of resources such as   journals, books, conference papers, theses and dissertations, preprints, abstracts, technical reports, patents etc. It is a good source for citations also.
2. OAIster (http://oaister.worldcat.org/) - It is a union catalog of millions of records that represent open access resources. This catalog was built through harvesting from open access collections worldwide using the Open Archives Initiative Protocol for Metadata Harvesting (OAI-PMH). It is managed by OCLC.
3.  Open Library (https://openlibrary.org) - It has 20 million edition records online, provide access to 1.7 million scanned versions of books, and link to external sources like WorldCat and Amazon. Open Library is building a catalog to share freely and openly with the public. Registration is required. It has different categories of books such as text books, fiction, non-fiction etc.
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