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