You can use Google to find primary resources. If you find a source that cites another source, that's a secondary resource, so don't use that. Go right to the actual source where the information came from, and use that. For example, if you find an article on Google that cites information from the CDC, you would need to go to the CDC's website and find the information there. The CDC would be the primary source in that case, not the article that cited information from it.