Web of Science. Content coverage for this database is focused on the sciences, medicine, and social sciences. Allows users to export a plain text or tab-delimited file or utilize the API, to obtain citation data. Data is limited to 100,000 records per query. UIC subscription required
Scopus. Content coverage for this database is multidisciplinary. Allows users to export a RIS or CSV (comma-separated values) file or utilize the API, to obtain citation data. Data is limited to the first 2,000 records in a query. UIC subscription required
Dimensions. This database's content coverage is focused primarily on the sciences, medicine, business, and social sciences. Allows users to perform powerful and complex queries with their API or export a CSV or Excel file. Queries are limited to the first 50,000 records with either method. UIC does not subscribe. Free version available.
Google Scholar. Content coverage for this search engine is multidisciplinary. Users can perform simple or more complex queries, but currently, no export method is available. There is no publicly available or subscription-based API. Free to access.