Perhaps you should try some spelling variations:
hanh truc » hang truc, nhanh thuc, hanh thuoc
hieu van » hieu va, thien van, lieu va
van hanh » van thanh, ban hanh, van anh
mang xa » lang xa, mang may, dang xay
truc va » thuc va, thuc vat, trung va
va hanh » va thanh, va danh, ban hanh
cua tre » cua te, cuu tre, cua triet
su xac » pu xac, su cac
xac ky » cac ky, sac ky, bac ky
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 xac ky ((mang xa) or (nang cao)) hoi. hieu van hanh truc va hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su xac ky ((mang xa) OR (nang cao)) hoi. hieu van hanh truc va hanh vi cua tre.
• Adding a wildcard symbol may retrieve word variants: su xac ky ((mang xa) or (nang cao)) hoi. hieu van hanh truc va hanh vi cua tre*.