Here are some search engines that allow you to find books, journal articles and even primary source material for whatever kind of research you are carrying out.
These are academic search engines for you
SEARCH ENGINES & RESEARCH RESOURCES
1. RefSeek: is a web search engine for students and researchers that aims to make academic information easily accessible to everyone. RefSeek searches more than one billion documents, including web pages, books, encyclopedias, journals, and newspapers.
2. Academic Info: From accreditation to test preparation, financial aid to our college guide, or simply looking to get some general information on getting started with online education, then this page is your gateway to all things academia related.
3. iSEEK Education: Put your mind at ease with safe search technologies and editor-reviewed content Search hundreds of thousands of trusted resources from universities, government, and established noncommercial providers.
13. Archives Hub: Use the Archives Hub to find unique sources for your research. Search across descriptions of archives, including links to digital content, held at over 300 institutions across the UK.
23. CiteSeerx: CiteSeerx is a digital library and an online academic journal that offer information within the field of computer science. It indexes academic resources through autonomous citation indexing system.
24. PLOS ONE: provides a free access platform to everyone searching for science-related information. All the articles publish on PLOS ONE are published after going through a strict peer-reviewed process.
25. Infomine: The Infomine is an incredible tool for finding scholarly Internet resource collections, especially in the sciences InfoMine provides comprehensive information on mining, the mining industry, mining technology and mineral exploration.