The databases listed below are good sources of top-rated academic journal articles and working papers in Economics and Finance.
Using them (rather than Web sources) will improve your chances of producing high quality work.
Review articles are also extremely helpful if you are doing a literature review for a dissertation. They are published in many journals. You can use "review", "overview" and similar words as keywords in your search. In Scopus you can limit your results specifically to review articles. Finally, there is a very useful publication, Annual Review of Economics, which publishes only review articles. You can search for relevant articles from it through the Annual Reviews database:
Other databases that also offer coverage of Economics:
Working papers, discussion papers and preprints are quite important in economics. They often present initial research thoughts and findings, and may later be published in modified form as a journal article. They are not peer-reviewed, but may be moderated by portals like SocArXiv that host them. They are nearly all free (open access), except for a few prestigious series like CEPR and NBER papers. Some useful sources of them include: