Connect to all Bibliographic Indexes* Page [Note: Page also links to full text archival collections]
*Bibliographic Indexes sometimes called "Research Databases"
Subject Indexes
Citation Indexes
Constructed to search forward and backward by citation, answering the question "Who cited my favorite article?" , the "Who cited the study citing my favorite article?" ETC.
Example: Web of Science
*Note: many subject indexes have limited forward citation searching, as does Google Scholar
Specialty Indexes by Document Type*
*many Bibliographic Indexes now use open URL to pull records from other archives into the Index [ or link out to the record] , so it may be transparent to the scholar whether the full text is part of the Bibliographic Index proper, or pulled into the search results. [It doesn't matter as long as you have the PDF.]
Hybrid Index / Archive