Perhaps you should try some spelling variations:
john ngosong » john song
young john » kong john, wong john, young jean
wang oanh » wang yan, wang yang, dang anh
oanh tran » anh tran, anh tuan, binh tran
duc ren » duc tran
vien » viens, vient, viren
sam » same, sham, syam

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

• Performing a fuzzy search may retrieve terms with similar spellings: wang oanh tran ((duc ren) or (duc vien)) young john ngosong sam ;~.
• If you are trying to use Boolean operators, they must be ALL CAPS: wang oanh tran ((duc ren) OR (duc vien)) young john ngosong sam ;.
• Adding a wildcard symbol may retrieve word variants: wang oanh tran ((duc ren) or (duc vien)) young john ngosong sam ;*.