Hints & Tips for Effective Searching
These hints are designed to help
you search any bibliographic database.
They were written with the biologist in mind.
- Don't over-limit by being too specific
in your search terms,
November 1, 2006
floral scent or scent production
mint or mints or mentha
mint or mints or mentha or spearmint or peppermint (etc.)
groundwater or ground water
- Don't limit by language until at the end of your search, and then, only if you've gotten a lot of "hits". Many of the databases have abstracts that are in English; so, even if you can't read the original article, much useful information can be gleaned from the abstract.
- Use truncation to pick up plurals and words
that are related.
volatile or volatiles or volatility
computers or computing or computational, etc.
gene or genes or genetic or genetically
- Use the correct truncation symbol for the search engine being used (?, *, $, +, !)
- Use Latin binomials as alternative terms.
- Think expansively when you're trying to
come up with alternative vocabulary.
For example, you may be interested in finding studies
that have examined pigment changes in plants, through time, in stems. Don't
just search for pigment* and stem*.
Also incorporate terms that express hypotheses about why the pigments may be changing... photoperiod? phytochrome? cold? degradation? And you'd want to search for the various types of pigments (e.g., chlorophyll, caroten?, etc).
- Don't be too quick to "and" terms together.
" AND" limits (restricts) your search. Before you "and", take the time to determine how many records you retrieve with just a simple search.
For example, if there were only 25 records about "mints" (see previous search), I'd probably look at ALL of them, and wouldn't worry too much about finding all the "scent" terms. I would, however, be on the lookout for terms that mean "scent", e.g., volatiles, because I might want to broaden my search to include other plant species than just the mints.
- If the search engine allows (e.g., OVID or SilverPlatter), search "or'd" terms on one line, and later "and" them. This way, if you later think of another term to "or", it can easily be done! For example:
- In databases where the whole search must be entered on one line (e.g., Web of Science; Purdue Catalog),
put parentheses around "or'd" terms:
For example, (scent* or volatile*) and (petal* or stamen* or pistil* or flower* or floral*)
Note: Don't "and" in these databases until you've determined the depth of the database for the terms of interest!
For example, search for "(scent* or volatile)" alone, before you add in "and (petal* or stamen* or pistil* or flower* or floral*)". Again the warning: don't be too specific, too quickly!
Use "not" to get rid of inappropriate retrievals.
Just as most search engines support "and" and "or", most also support "not". Use this when you're getting a lot of "hits" in a subject that is not of interest. For example, if, when searching for articles on plant stems, I found a lot of articles that were about stem cell research in animal systems, I could just add "not stem cell" to my earlier search:
Stem* not stem cell*
Beware of spelling!
If you get zero hits, suspect that you've misspelled something!
Subject Headings, Descriptors, Identifiers, and Keywords.
Descriptors and subject headings come from a standardized list of vocabulary (a thesaurus) that the database provider has devised and is applying to describe specific concepts. They can be used to pull together related articles. "Keywords" are generally non-controlled vocabulary, which enhance one's understanding of the topic of the paper. All of these terms or phrase may give you ideas for additional vocabulary terms for your search.
- If you're using a database that has subject headings, descriptors, or keywords, be sure to examine them.
- Sometimes, by reviewing the controlled vocabulary, you'll discover that the database provider is using
- "Keywords" are generally non-controlled vocabulary. This means that, for example, the word "plants" may be in the keyword field for some articles about plants, but it may not be in the keyword field for all articles about plants. Use keywords as a source of additional vocabulary, but don't expect them to be hot-linked or standardized (e.g., Current Contents).
They may give you ideas for additional vocabulary terms or phrases. In many cases, the terms will be "hot-linked", which allows you to search them, immediately.For example, when I searched for "floral scent," an appropriate CAB descriptor was "essential-oil-plants." So, now I'd re-formulate my search, adding the term "essential oil plants", a term I probably wouldn't have thought of on my own!!
Use descriptors and subject headings as a source of related articles. After you do a free-text search, examine the "good" records closely, to see if any of the descriptors or subject headings describe an aspect of the topic you're looking for. Re-do your search, using these terms or phrases; they will pull together articles that may have been missed during the earlier search. Identifiers are usually terms that are under consideration for addition to the authorized list of descriptors; use them, too, to increase your vocabulary (found in Agricola, Compendex).Some databases have a built-in thesaurus (e.g., CAB Abstracts, Food Science & Technology Abstracts) for descriptor terms.
Use the thesaurus to find "related words",
or "narrower terms", or "broader terms".Use the automatic mapping feature, when
Some databases have a built-in feature that will "map" free-text terms to the appropriate subject heading, automatically (e.g., Compendex, Medline). Many times you'll find that you'll use the recommended subject heading, but also want to use your free-text. Databases that "map" to the appropriate subject heading often have a feature that will let you "explode" your search, so you're picking up all the sub-headings under a term, too.
alternative spelling as
their standard term.
e.g., CAB Abstracts uses "soyabean" rather than soybean!