BOX 6.1 Methods of Searching the TEHIP Databases
Grateful Med: Grateful Med was developed to simplify MEDLINE searching. However, input screens have gradually been added for other databases, and users can now access 20 NLM databases through Grateful Med. Grateful Med currently offers input screens for all of the TEHIP databases except DART/ETICBACK, EMIC/EMICBACK, GENE-TOX, and TRIFACTS. In 1996 Internet Grateful Med was introduced and is currently available for searching MEDLINE, HealthSTAR, AIDSLINE, and PREMEDLINE.
Direct Searching: The only fully operational method available for accessing all of the TEHIP databases is direct searching using NLM's search command language. Direct searching involves the use of commands, mnemonics (abbreviations indicating database fields), and Boolean logic for combining terms. This interface requires a high level of search proficiency and expertise.
Menu Searching: Two of the TEHIP databases, TRI and HSDB, have menu search interfaces with step-by-step options for assisting users in developing a search strategy.
Experimental World Wide Web Interface: SIS staff are in the process of developing a new approach to searching the TEHIP databases that uses the hypertext and graphics capabilities available through the World Wide Web.
workstations in health science libraries, fewer library workstations provide end-user access to the TEHIP databases.
NLM is in the somewhat unique position of playing a number of different roles in the database process. For a few of the TEHIP databases, such as HSDB and ChemID, NLM is the creator of the database and is responsible for the content. In other cases, such as CCRIS and IRIS, other federal agencies are responsible for content and NLM is responsible for maintaining the database on the NLM computer servers (see Chapter 2). These agencies may provide additional access points for their databases such as leasing them in online or CD-ROM formats. For all of the databases in the MEDLARS system, NLM acts as a database provider and offers online search access for registered users. Additionally, NLM as a database producer leases its databases to commercial vendors, academic institutions, libraries, and other organizations. The result is a variety of access routes available to users interested in searching the NLM databases. However, the number of access routes varies depending on the specific database (Figure 6.1). MEDLINE is offered by many commercial vendors in numerous CD-ROM and online formats, and most health science libraries and biomedical organizations provide their users with access to MEDLINE. On the other hand, the more specialized databases have fewer points of access, and there is only one access point—direct searching—that allows the user to connect with the entire TEHIP complement of all 16