Examine search result record to see what subjects have been assigned (if any) to the record. Subjects can be combined with keywords to focus search, or searched individually to find items that are primarily about the topic.
Use refine or limit features such as date, material type (e.g., review article), treatment (in Compendex - theoretical, applied, etc).
Expand to related articles with shared citations (Scopus database allows for this)
Use citation sorting and browsing features, including sorting by # of times cited (Scopus, SciFinder, etc)