Chemical bibliographic databases: the influence of term indexing policies on topic searchesElectronic supplementary information (ESI) available: Additional information on the diversity of studied domains (Table S1), on the expanded timespan from 1990-2005 (Table S2), the studied references in Table 8 (Doc 1), the studied references in Table 10 (Doc 2) and the source code of the script (Doc 3). See DOI: 10.1039/c5nj01077b

A comparative study of the three main chemical information systems (Scifinder, Web of Science and Scopus) was performed by studying the indexing policies of titles, abstracts and keywords within selected literature articles. Various chemical expressions were introduced as topic searches to illustrate the different search tools related to term indexing. The resulting article lists were compared two-by-two by means of a script designed to identify common reference lists and specific ones to each editor. Analyzing these specific reference lists reveals that only partial coverage areas of references should be expected when querying a single platform. The discussion covers the term and keyword indexing policies, their influence on the retrievability of references and on the retrievability of the highly cited papers. How many articles can we retrieve from a topic search in chemical bibliographic databases?