RESUMO
BACKGROUND: Concepts for medicinal plants are represented by a variety of associated general terms with specific indexing patterns in databases, which may not consistently reflect growth of records. OBJECTIVES: The objectives of this study are to assess the development in databases by identifying general terms that describe herbal medicine with optimal retrieval recall and to identify possible special trends in co-occurrence of specific and general concepts. METHODS: Different search strategies are tested in cab abstracts, medline and web of science. Specific terms (Origanum and Salvia) are employed. Relevant general terms (e.g. 'Plants, Medicinal', Phytotherapy, Herbal drugs) are identified, along with indexing trends and co-occurrences. RESULTS: Growth trends, in specific (narrower) terms, are similar among databases. General terms, however, exhibit dissimilar trends, sometimes almost opposing one another. Co-occurrence of specific and general terms is changing over time. CONCLUSIONS: General terms may not denote definite development of trends as the use of terms differs amongst databases, making it difficult to correctly assess possible numbers of relevant records. Perceived increase can, sometimes, be attributed to an increased occurrence of a more general term alongside the specific one. Thesaurus-controlled databases may yield more hits, because of 'up-posted' (broader) terms. Use of broader terms is helpful as it enhances retrieval of relevant documents.