/sys$common/syshlp/helplib.hlb PRODUCT, SHOW, HISTORY, Qualifiers, /SINCE  *Conan The Librarian (sorry for the slow response - running on an old VAX)

       /SINCE=time

    Selects records that were created on or after the specified
    date and time. You can specify time as an absolute time, as
    a combination of absolute and delta times, or as one of the
    following keywords:

       TODAY (default)
       YESTERDAY

    Refer to the OpenVMS User's Manual for information about
    specifying time values.