Perhaps you should try some spelling variations:
vu khach » vu khanh, vu khac, vay khach
hieu van » hieu va, thien van, lieu va
van pham » san pham, van phan, van phat
duc ngan » duc ngon, duc nhan, luc ngan
ty hang » ly hang, thi hang, thu hang
hang vi » hang va, hanh vi, hang di
vi cua » vai cua, di cua
cua te » cua tu

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

• Performing a fuzzy search may retrieve terms with similar spellings: vu khach ((ty hang) or (ty xang)) xa hoi. hieu van pham duc ngan hang vi cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu khach ((ty hang) OR (ty xang)) xa hoi. hieu van pham duc ngan hang vi cua te.
• Adding a wildcard symbol may retrieve word variants: vu khach ((ty hang) or (ty xang)) xa hoi. hieu van pham duc ngan hang vi cua te*.