The following are databases that allow you to search a large number of periodicals. In some cases you will be searching the full text of articles by default, in other cases only the title, abstract, and subjects. Look for an "Advanced Search" link to see more options. See the Search Tips page to review the tips we went over during the orientation.
These organizations produce research on a large number of issues, most of which they make freely available online. They are biased; they are trying to influence policy. So you should be aware of their orientation and take it into account when you quote their reports. Use the site's search box, or browse the section called "reports," "research" or something similar.