Q. Is there a way to limit search results in SLUth to primary or secondary sources?

There is a way to limit your search results to primary sources in SLUth, BUT it's not always reliable. This is because determining whether or not a source is primary or secondary has everything to do with context.

For example, if you were researching global warming....

• an article about global warming that was written during the 1990s would be a secondary source. 

If you were researching how people talked and wrote about global warming in the 1990s...

• the SAME article about global warming that was written during the 1990s would be a primary source.

That being said, there is a way to limit by Source Type to primary sources in SLUth. See screenshots below. 

There's no way to limit search results to secondary sources in SLUth, but the vast majority of the sources found in SLUth will be secondary in nature. Again - this is all based on context.