How to Do Library Research

This set of pages has information on how to do library research. In all cases, once you have located sources, be sure to evaluate them, using the evaluation guides.

Using Preferred Terms: Examples


In science indexes, the preferred subject term for a plant or animal is usually the scientific classification (Genus and species) .  There are reference books with these terms (which often are in Latin), but you might also try your search in English (or whatever language is easiest for you) and see if there are any items on your topic.  If there are, look in the subject field for the term or terms used in the database and do another search with the preferred term.

Plant example

In AGRICOLA, a search for snapdragons finds among the 260 results the following article:

"Yield, quality and profitability of sensor-controlled irrigation: a case study of snapdragon (Antirrhinum majus L.) production."
Irrigation science, 2016 Sept., 34.5 p. 409-420.

When you look in the DE (Descriptors) field, you see the following:

Antirrhinum majus; case studies; crops; cultivars; cut flowers; disease incidence; electricity; greenhouses; harvest date; income; irrigation scheduling; irrigation systems; labor; on-farm research; profitability; sales; stems

A new search for "antirrhinum majus" identifies 1477 records.  If you plan on narrowing your search to something specific, such as "crops," you will get better results with antirrhinum majus than with snapdragons.  In this instance, with antirrhinum majus you find 33 records instead of 0.  The differences may not always be this dramatic, but it is always a good idea to do your search with the preferred term.


Search  Results  (Oct. 26, 2017)
snapdragons  260
antirrhinum majus  623 (436 as a subject)
snapdragons AND crops  0
antirrhinum majus AND crops  33
(antirrhinum majus OR snapdragons) AND crops  50

To make sure you are catching as much as possible, do a search with both the Latin and English term.

Animal example

When doing research on conservation of the gray wolf, it is better to search for "Canis lupus."  A search in CAB Abstracts  locates:

CAB Abstracts 1973-  Results (Oct. 26, 2017)    
gray wolf  352
gray wol*  355
Canis lupus  1272
conservation  291,544
(gray wolf or gray wol*) AND conservation  105
Canis lupus AND conservation  323
(canis lupus OR gray wolf OR gray wol*) AND conservation     353

This example also shows how the preferred term can make a difference in the number of items identified. Do a search with the Latin and English term to be sure to identify the most records.


These are just a few examples showing the importance of using preferred subject headings. Most library databases use subject terms.

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