Citation indexes allow a researcher to trace the impact of an article upon later publications.
ISI produces three web-based citation indexes, covering the years 1980 to present. They are all accessible through the OhioLINK Research Databases. Carlson Library also has print editions of these indexes available for years prior to 1990. Or, from the library's home page you can connect to OhioLINK, Research Databases, and choose the Science and Technology subject category. From the list of databases, click on Science Citation Index Expanded.