Perhaps you should try some spelling variations:
cham thuc » nham thuc, pham thuc, tham thuc
vu khach » vu khanh, vu khac, vay khach
khach ky » hanh ky, thanh ky
day hanh » day nhanh, day thanh, dao hanh
dac nhan » cac nhan, danh nhan, ca nhan
hieu va » lieu va
cua tre » cua te, cuu tre, cua triet
de cua » le cua, te cua, dieu 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 ky nang x ho. ((hieu va) OR (hieu qua)) cham thuc ((day hanh) or (dac nhan)) de cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu khach ky nang x ho. ((hieu va) OR (hieu qua)) cham thuc ((day hanh) OR (dac nhan)) de cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "vu khach ky nang x ho. ((hieu va) OR (hieu qua)) cham thuc ((day hanh) or (dac nhan)) de cua tre".
• Adding a wildcard symbol may retrieve word variants: vu khach ky nang x ho. ((hieu va) OR (hieu qua)) cham thuc ((day hanh) or (dac nhan)) de cua tre*.