OneSearch is provided by EBSCO, the same vendor that produces Academic Search Complete, and the two products share many of the same features.
Results may be limited to articles from Peer Reviewed journals.
If an item is used, it must be cited. Look for the CITE button in the right margin of the article's landing screen.
Look at the search results carefully: there will be a mixture of source types and quality.
OneSearch may provide a "Start Your Research" feature (not one of the results depicted here), which leads to an overview essay from an online encyclopedia. This would be reliable background information, but it is not considered scholarly.