Google Scholar is a useful search tool as it makes use of Google's sophisticated search algorithms and allows natural language searching to locate resources such as articles, theses, books, abstracts and court opinions.

You can use Google Scholar to locate freely available resources, however without having an institutional login you will not be able to access everything in your search results.

BASE – Bielefeld Academic Search Engine

• Search engine for academic resources
• More than 100 million documents, from more than 5,000 sources
• Full text of 60% of documents available for free (open access)
• Journals, newspapers, books, musical notation, maps, audio, images and video, datasets, software.

DOAB: Directory of Open Access Books

• Searchable index of peer reviewed books published under open access and freely available.
• Browse by subject to find books in a variety of subject areas.

Open Library

• Free digital lending library of over 2 million eBooks, including textbooks, plays, and key texts in science, literature, art, etc.

CK-12

• Study guides, simulations, interactive learning, practice units – real world applications, videos, flashcards, assessments e.g. physics simulations, maths practice tests, review scientific concepts
• Also has free eBooks.

World Digital Library

• Digitisations of Primary Source material from around the world, across wide variety of subjects and time periods.