Scopus covers more than 21,000 peer-reviewed journals from over 5,000 international publishers with records going back to 1823. It is considered to be the largest abstract and citation database. Use it for searching for research articles, conference papers, preprints, and patents. Also discover who is citing whom, citation counts, and h-index score – an author-level metric.
In case you are wondering about the difference, see this Scopus vs Web of Science Comparison Chart.