BUMC MEDLINE PLUS SEARCH TIP:
TRUNCATION & WILD CARD CHARACTERS


Truncation is used to ensure retrieval of all possible variations of a term or phrase. Search statements can be truncated by entering the truncation characters, a dollar sign $ or a colon : at the end of the phrase. Truncation can be used with any digit to indicate the maximum number of characters that may follow the search term or phrase.


TRUNCATING TEXTWORD SEARCHES
Textword truncation is used most frequently to retrieve word variations that appear in the titles and abstracts (textwords) of journal articles. For example, to retrieve hypnotize, hypnotized, hypnotizing, hypnosis, hypnotics and any other variation in titles and abstracts (textwords), you could use truncation:

hypno$ or hypno$6

See the two examples below:


Truncation should be used with caution. If you truncate too near the beginning of a word or phrase, particularly if you fail to limit truncation with a number, your search may result in a high number of irrelevant documents. For example, rat$ would retrieve rat, rats, ratio, rational, rationale, rate, etc. Truncation can only be used with at least two characters to the left of the truncation. The statement f$ is not allowed.


WILD CARD CHARACTERS
Wild card characters are like truncation, in that they allow for variations of title and abstract words (textwords) to be retrieved.

A wild card in the form of the pound sign # can be used to substitute for one character, and is useful for finding plural forms of textwords. For example, wom#n will retrieve woman or women.

Another wild card is the question mark ? which is used as a replacement for 1 character or no characters in textword searching. This wild card character is useful for British/American word variants, since it specifies that you want retrieval whether an extra character is there or not. For example, to locate occurrences of color or colour you could enter colo?r and both color and colour will be retrieved. As with regular truncation it is not possible to apply the ? character in a word if there is only one letter in front of the truncation. For example, f?etal can not be searched.


TRUNCATING AUTHOR SEARCHES
Truncation can also used with author searching to retrieve all forms of an author's name. For example, if you are looking for articles published by a Dr. Bernard, but you do not know her first name and middle initial, truncate the author search:

bernard-$.au.
 Retrieves all articles written by any author whose surname is Bernard, regardless of the author's first name & initials. This search would retrieve articles by Audrey Bernard, Brendan James Bernard, Cathleen Bernard, Doris Ann Bernard, Ethan L. Bernard, etc.
bernard-s$.au.
 Retrieves all articles written by S. Bernard, regardless of the middle initial. This search would retrieve articles by Selma J. Bernard, Sylvia Garland Bernard, Samuel Bernard, Stanley F. Bernard, etc.

All author searches using the truncation character should be typed on the "enter subject" prompt. This is called direct entry. Click here for more information on using direct entry commands to bypass menu options.


Sometimes, authors use variations of their names when publishing, so truncation helps guarantee that you won't miss finding articles simply because of inconsistencies in the author's name. For example, Thomas E. Starzl, a transplant surgeon, has published hundreds of articles in the biomedical journal literature. Usually, he uses his full name when publishing -- Thomas E. Starzl. Occasionally, Dr. Starzl publishes as Thomas Starzl -- eliminating his middle initial. To find Dr. Starzl's publications, you could search for:

starzl-te.au.
 Retrieves all articles written by Thomas E. Starzl.
starzl-t.au.
 Retrieves all articles written by Thomas Starzl. This strategy does NOT retrieve articles by Thomas E. Starzl, however, because no truncation symbol was used for the middle initial.
starzl-t$.au.
 Retrieves all articles written by Thomas Starzl, regardless of whether he used his middle initial when publishing.
starzl-$.au.
 Retrieves articles by Starzl, regardless of the first name and middle initials used. If you knew that a Dr. Starzl had published a number of articles about transplantation, but didn't know that the doctor's name is Thomas, you could use the truncation symbol in place of the first and middle names.

Notice below that search results vary dramatically based on how the truncation symbol is used:


TRUNCATING JOURNAL SEARCHES
Truncation can used with journal title searching to retrieve various journals whose titles are similar:

journal of pharmac$.jn.
 Retrieves Journal of Pharmacy and Pharmacology, Journal of Pharmacological Methods, etc.
transplan$.jn.
 Retrieves the journals Transplant Immunology, Transplant International, Transplantation, and Transplantation Proceedings.

All journal searches using the truncation character should be typed on the "enter subject" prompt. This is called direct entry. Click here for more information on using direct entry commands to bypass menu options.



For more information on using truncation in BUMC MEDLINE Plus, contact a reference librarian at 617-638-4271 or refquest@med-libwww.bu.edu.

BUMC MEDLINE Plus search tips are published monthly. All search tips are archived at http://med-libwww.bu.edu/library/searchtips.html.