Biomedical Engineering Reference
In-Depth Information
The major downside of Networked Entrez is that data outside of the Entrez system aren't available by
simply clicking on hypertext links, as they are in the Web version of Entrez. A minor limitation of the
local version is that it must be updated periodically in order to have the latest version. The most
obvious benefit of a Web-delivered system that runs under a browser is that updates to the interface
and the underlying search engine are transparent and instantaneous. The burden of application
maintenance is fully on the shoulders of the NCBI staff and their affiliates, freeing users from having
to manually update local copies of a search engine or user interface.
Trading a more flexible user interface and faster execution for lack of instant connectivity to other
online resources and the need to periodically update the local application is more of a personal
decision that doesn't affect the quality of data available through the Entrez system. Both versions of
Entrez provide a common user interface, specifying subjects, ranges, Boolean operators, and other
search criteria. Search results may be reviewed in a variety of formats, saved to disk or to the
clipboard, or printed. In addition, the results can be incrementally refined if the user continually
narrows the search criteria, working from the results of previous searches that are temporarily
maintained in the system's memory. The discussion that follows assumes that the more popular Web
browser version of Entrez is used.
The major search features of the Entrez system include a variety of tools to define and refine a
database search (see
Figure 4-4
). These tools support selecting a database, linking, imposing limits
on searches, using indexes and the search history in searches, and saving results to a clipboard. In
addition, the tools support searching by a variety of topics, searching within a specified range,
truncating searches, using Boolean operators to narrow searches, and advanced search authoring
capabilities to supplement menu-driven search commands.
Figure 4-4. Entrez-Enabled Search Process. Entrez hides the underlying
complexity of online molecular biology databases, facilitating the iterative
process of submitting search criteria, viewing results, and refining or
narrowing the search until the desired results are achieved.
