Use Google Scholar to find articles from a wide variety of academic publishers, professional societies, preprint repositories and universities, as well as scholarly articles available across the Web. A drawback is that not all articles are free.
Academic Search Complete is the world's most valuable and comprehensive scholarly, multi-disciplinary full-text database, with more than 8,500 full-text periodicals, including more than 7,300 peer-reviewed journals.
In addition to full text, this database offers indexing and abstracts for more than 12,500 journals and a total of more than 13,200 publications including monographs, reports, conference proceedings, etc. The database features PDF content going back as far as 1887, with the majority of full text titles in native (searchable) PDF format. Searchable cited references are provided for more than 1,400 journals.
History Reference Center offers full text from more than 1,620 reference books, encyclopedias and non-fiction books, cover to cover full text for more than 150 leading history periodicals, nearly 57,000 historical documents, more than 78,000 biographies of historical figures, more than 113,000 historical photos and maps, and more than 80 hours of historical video.
The Philosopher's Index is an easy-to-use subject and author index which will be very helpful to philosophy scholars. The database indexes over 680 academic philosophy journals, as well as books and anthologies. The index includes journal articles from over 40 countries and is updated quarterly. A book review index is also included.