Use the EXPLODE Command to Retrieve Comprehensive Results?

TOPIC: A technique that can help you narrow your results is the EXPLODE feature. This feature is designed to take advantage of the hierarchical organization of online thesauri. It speeds retrieval by automatically selecting a term plus narrower related terms. Results vary depending on the type of thesaurus in the database. To EXPLODE a term, SELECT the term with an ending exclamation point (e.g., fuel!).

Dialog thesauri are constructed in two forms. In one form, using the EXPLODE feature will retrieve all of the narrower terms for all hierarchies (e.g., GeoRef (File 89)). In the other form, EXPLODE retrieves only the narrower terms immediately below the descriptor. It works this way because the thesaurus does not group all hierarchies under one descriptor, but rather retains levels of hierarchies, all of which may have narrower terms (e.g., Inspec® (File 2)). The EXPLODE feature works equally well with both types of thesauri, but you need to be aware of which thesaurus type you are exploding from, and then review your results accordingly.

In this example we'll be looking for narrower terms for "semiconductors" in Inspec.

COMMAND SUMMARY

BEGIN 2
EXPAND (SEMICONDUCTORS)
SELECT (R1, R3:R12)/DF
SELECT SEMICONDUCTORS!

HOW TO...

1. BEGIN File 2, which has a thesaurus that retrieves narrower terms immediately below the descriptor. 2. EXPAND on a term within parentheses to directly access the Related Terms display (rather than expanding twice). R1 includes all occurrences of the term in the Basic Index. Note the narrower (N) terms also.

3. Limit your narrower terms using the /df (descriptor full) index. This looks for the terms as exact phrases rather than searching on the individual terms within them. 4. EXPLODE the term using an explanation point at the end of the term. Note identical retrieval—exploding the term is the same as selecting the term and all narrower terms from the EXPAND list and limiting to the full descriptor (/DF).

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Stock #: 53712; Last modified: 14 Sep 2011

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