Truncation Symbols ("Wild Cards")

Use truncation symbols to allow for various word forms of your search terms.

Symbol Definition Example Retrieval

? Any number of characters
(including none), usually at the
end of a term* STEROID? STEROID
STEROIDS
STEROIDAL

# One or zero characters,
at the end of a term VAP#### VAPOR
VAPORS
VAPOUR
VAPOURS

! One character, at the end or within a term WOM!N WOMAN
WOMEN

Symbol	Definition	Example	Retrieval
?	Any number of characters (including none), usually at the end of a term*	STEROID?	STEROID STEROIDS STEROIDAL
#	One or zero characters, at the end of a term	VAP####	VAPOR VAPORS VAPOUR VAPOURS
!	One character, at the end or within a term	WOM!N	WOMAN WOMEN

* In the Basic Index of the CAplus file, truncation is allowed at the beginning of a term (?BACTERIA)

Reproduced with the permission of CAS, a Division of the American Chemical Society, from "Tips for Searching the CAplus & REGISTRY Files." (CAS9613-0298)