Perhaps you should try some spelling variations:
vie » viet, view
viec » vietc, viewc, viet
vien » vietn, viewn, viet, bien
vienam" » vietnam", viewnam", vietam", bienam", vietnams"
vientnam" » vietntnam", viewntnam", viettnam", bientnam", vietnams"
vietnam" » viettnam", viewtnam"
president » resident, present

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: "(vie or (viec OR vien)) (president or residents) of (vienam" or (vientnam" or vietnam"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: "(vie or (viec OR vien)) (president or residents) of (vienam" OR (vientnam" or vietnam")).
• Removing quotes may allow a broader search: (vie or (viec OR vien)) (president or residents) of (vienam or (vientnam or vietnam )).
• Adding a wildcard symbol may retrieve word variants: "(vie or (viec OR vien)) (president or residents) of (vienam" or (vientnam" or vietnam"))*.