UD Update Code

(a limit field)

1969 in ud

ud=19971123

ud>19971213

The UD field contains the date the source document was received at BIOSIS. Update code format and availability vary. In data added to the database from 1969 through 1992, the date format is YYYY; in data added to the database from 1998 onward, the date format is YYYYMMDD.

Browsing Update Codes

As an alternative to searching with the field label, you can browse codes and search for them directly from the Update Code Field-Specific Index. This field-specific index contains only codes drawn from the UD field, therefore, your search will always yield results. Search results display in the UD field.