If you use SourceSafe for source code control with Access, you can search
the SourceSafe project. All references except tables will be found since all
objects except tables are stored as text in SourceSafe.
You can mimic SourceSafe's conversion of objects to text using the
undocumented function Application.SaveAsText(objectName). That might not be
the correct syntax, but you can find it by web search. You could write a
loop to process all db objects and output them as text files. Then search
the folder containing the text files for the desired string.
As John suggested, FMS makes Total Access Analyzer which includes
comprehensive cross-reference documentation, but it's not free.