Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
hieu van » hieu va, thien van, lieu va
tu sach » thu sach, su sach, te sach
nang ma » tang ma, sang ma, nang cao
van tac » van thac, van tai, van tan
tac dat » tac da, tac dao, tac dau
dat ban » bat ban, da ban, day ban
vai cua » dai cua, hai cua, lai cua
ma hoi » mai hoi, xa hoi, ma hoa
vi 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: ((thu hoach) or (tu sach)) ky nang ma hoi. hieu van tac dat ban thanh ((vi cua) or (vai cua)) vat~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((thu hoach) OR (tu sach)) ky nang ma hoi. hieu van tac dat ban thanh ((vi cua) OR (vai cua)) vat.
• Adding a wildcard symbol may retrieve word variants: ((thu hoach) or (tu sach)) ky nang ma hoi. hieu van tac dat ban thanh ((vi cua) or (vai cua)) vat*.