General Research Tools
(for preliminary research, scanning the literature, refining the topic)

• Catalyst (books and articles)
• Google Scholar (better at search in full text)
• Refworks (or other citation management tools)

Further Research Tools
(finding articles in specific fields, related articles, grey literature)

• SSCI,  Scopus, Dimensions, Google Scholar (for citation tracking)
• Dissertations and Theses Global

Primary Sources

• Gale Primary Sources
• AM Explorer
• News and Newspapers 
• East Asian language sources