Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
voi hoat » toi hoat, doi hoat, vo hoat
vat hanh » vat thanh, van hanh, va hanh
nam thuc » nam thuoc, am thuc, nam thu
tang ma » mang may, tang van
ky tang » ky nang, ky dang, kho tang
su xach » su sach
ma hoi » mai hoi, xa hoi, ma hoa
vi hoa » voi hoa, vi hoc, va hoa
su xac » pu xac, su cac

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) or (su xach)) ky tang ma hoi. hieu van nam thuc vat hanh ((vi hoa) or (voi hoat)) viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su xac) OR (su xach)) ky tang ma hoi. hieu van nam thuc vat hanh ((vi hoa) OR (voi hoat)) viet.
• Adding a wildcard symbol may retrieve word variants: ((su xac) or (su xach)) ky tang ma hoi. hieu van nam thuc vat hanh ((vi hoa) or (voi hoat)) viet*.