Perhaps you should try some spelling variations:
dieu hien » dieu khien, dieu kien, bieu hien
hieu hien » bieu hien, chieu chien, dieu khien
vu khach » vu khanh, vu khac, vay khach
hanh lai » hanh lam, hanh tai, thanh lap
khach ky » hanh ky, thanh ky
nang xa » nang x, lang xa, nang ma
lai cua » dai cua, hai cua, lai chau
va hanh » van hanh, va thanh, va danh
cac lo » cac lop, cac co, cac bo
cua te » cua tu
lo va » lo van, lao va, ly va

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 ky ((nang xa) or (nang cao)) hoi. ((hieu hien) OR (dieu hien)) cac lo va hanh lai cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu khach ky ((nang xa) OR (nang cao)) hoi. ((hieu hien) OR (dieu hien)) cac lo va hanh lai cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "vu khach ky ((nang xa) or (nang cao)) hoi. ((hieu hien) OR (dieu hien)) cac lo va hanh lai cua te".
• Adding a wildcard symbol may retrieve word variants: vu khach ky ((nang xa) or (nang cao)) hoi. ((hieu hien) OR (dieu hien)) cac lo va hanh lai cua te*.