Perhaps you should try some spelling variations:
vu khach » vu khanh, vu khac, vay khach
van lang » van nang, va lang, van dang
van hang » van khang, van hoang, van thang
cham luc » cham soc, nhan luc, cham cuu
su sach » so sach, vu sach
hieu vu » hieu va, hieu ve, hieu su
vu cham » va cham, vu kham, tu cham
va hanh » van hanh, va thanh, va danh
luc va » duc va, tuc va, loc va
vi cua » vai cua, di cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((su sach) or (vu khach)) ((van lang) OR (van hang)) xa hoi. hieu vu cham luc va hanh vi cua vat~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sach) OR (vu khach)) ((van lang) OR (van hang)) xa hoi. hieu vu cham luc va hanh vi cua vat.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((su sach) or (vu khach)) ((van lang) OR (van hang)) xa hoi. hieu vu cham luc va hanh vi cua vat".
• Adding a wildcard symbol may retrieve word variants: ((su sach) or (vu khach)) ((van lang) OR (van hang)) xa hoi. hieu vu cham luc va hanh vi cua vat*.