Perhaps you should try some spelling variations:
vu khach » vu khanh, vu khac, cua khach
hieu van » hieu va, thien van, lieu va
thanh va » thanh van, hanh va, thanh ha
luc gia » luoc gia, duc gia, quoc gia
cac luc » cau luc, coc luc, cac nuoc
cua tre » cua te, cuu tre, cua triet
hieu ve » hieu va
lang xa » lang ha, dang xay, lang van
ky lang » ky nang, ky dang, ky tang
va cua » va chua, via cua, ca cua

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) OR (vay khach)) ky lang xa hoi. ((hieu ve) or (hieu van)) cac luc gia thanh va cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((vu khach) OR (vay khach)) ky lang xa hoi. ((hieu ve) OR (hieu van)) cac luc gia thanh va cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((vu khach) OR (vay khach)) ky lang xa hoi. ((hieu ve) or (hieu van)) cac luc gia thanh va cua tre".
• Adding a wildcard symbol may retrieve word variants: ((vu khach) OR (vay khach)) ky lang xa hoi. ((hieu ve) or (hieu van)) cac luc gia thanh va cua tre*.