Scopus includes a few very useful ways to analyze articles in groups, either as a collection of search results or as the articles that all cite a particular article. Here is an image of the "Documents by type" graph for articles in a search, showing the formats of every work in this particular search.
Web of Science includes ways to analyze search results and run "citation reports," which can analyze all the works citing articles in a search. This is a graph showing the items published in each year that cite the works found in a list of search results. WoS can also do a "citation map" for a particular article that shows the works citing and/or works cited by that article.