If the report is based on a query you already have built, then you can point the criteria of the specific fields in the query at a Form. For example, if you want to pull up a specific part # then have an unbound textbox on a form called PartNumber. In the criteria of the query add the following:
[Forms]![NameofForm]![PartNumber]
The query will only pull that specific part number and pass it to the report.
HTH