All of these databases includes scholarly articles, with each having a different emphasis -- policy, politics, sociology, business, etc. After searching, you can narrow your search to just scholarly articles by choosing "academic journals" or "peer reviewed." Try also resorting by "Relevance."
These journals are a sampling of what is available in the databases listed above. You can use the E-Journal Finder to look up additional journals of interest.
E-reference sources are helpful if you need background information on a concept or topic.