Navigate to Administration -> System Configuration and select Mobile from the drop-down menu.

Find the setting Wildcard Search for Products:

• True: Scanned or entered Part Numbers will be treated as a "contains" search. All values that "contain" the scanned/entered text will be returned.
• False: Scanner or entered Part Numbers will be treated as an "exact match" search. Only the exact match of the scanned/entered text will be returned.