The journal publisher: Elsevier 

One example of the synergies that are possible are the links that are planned between ScienceDirect and the ISIS™ service of MDL, the chemical software and information company that joined Elsevier Science in 1997. ... It would be natural to link through to the full text of the referenced articles, for example, or search the chemical structures in the full text database.  The intent is to develop over time sophisticated cross-database access for customers of both services. 

Hunter, K, ScienceDirect™. Serials Librarian, vol. 33, no. 1-4, April 1998