These databases contain articles from newspapers and magazines. Nexus Uni and Academic Search Premier contain other kinds of sources as well, but have filters you can use to limit your searches to news sources.
Many news outlets with an established or emerging prominence within the political press are available online - newspapers like The Washington Post and The New York Times, magazines like The Nation and National Review, or websites like Politico or Daily Kos.
You can use Google Advanced Search to find articles within those publications about your candidate, provided the content is free online and doesn't require a log-in or subscription.
Enter search terms in the "all these words" and/or "this exact word or phrase" boxes. Use your candidate's name, or choose other words representing issues or geographic areas of interest to you.
Put a website, newspaper, or magazine's URL in the "site or domain" box.
These pages feature public opinion polls about candidates, elections, and political issues. All of them have at least some polling relevant to this year's primary elections.
There resources are useful for finding biographical information about your candidate. They include information about things like previous offices held, careers before politics, educational backgrounds, families, etc.
You can also, of course, search for your candidate's official website and find biographical information there.