Despite the growth in number of online bibliographic databases available to assist scholars seeking information in the humanities, it remains a matter of concern to librarians and information professionals that these research tools are not as widely used as they might be. This report surveys a selected group of online databases (i.e., "America: History and Life,""Arts and Humanities Search,""Art Literature International,""Artbibliographies Modern,""Historical Abstracts,""Linguistics and Language Behavior Abstracts,""MLA Bibliography,""Philosopher's Index," and "Religion Index") to identify conceptual relationships between the different disciplines (i.e., art, history, literature, music, and interdisciplinary studies) in the humanities. A comparison is made between the effectiveness of natural language and controlled vocabulary for maximizing recall and the degree of uniqueness of records retrieved from the various files using four search types: (1) single subject terms of a specific nature; (2) single subject terms of a generic nature; (3) subject phrases; and (4) single subject terms combined with the Boolean "AND." The results demonstrate the possibilities for more productive use of online bibliographic databases as a resource for scholarly research in the humanities. Nine tables present the results analyses of the data. (34 references) (Author/SD)