Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
va thanh » gia thanh, ban thanh, va tinh
van cac » van hac, van cau, van bac
va dinh » van dinh, va kinh, va tinh
cac dat » cac dan, cai dat, cac dai
tu sach » thu sach, su sach, te sach
sach ty » sach y, sach tu, sach thu
dai hoi » dai hoc, dai hai, dai moi
tai hoi » tai khoi, tai hai, tai hoe
ty nang » ky nang, ty xang, ty hang
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: tu sach ty nang ((tai hoi) OR (dai hoi)). hieu van cac dat ((va thanh) or (va dinh)) vi cua vat~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty nang ((tai hoi) OR (dai hoi)). hieu van cac dat ((va thanh) OR (va dinh)) vi cua vat.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ty nang ((tai hoi) OR (dai hoi)). hieu van cac dat ((va thanh) or (va dinh)) vi cua vat".
• Adding a wildcard symbol may retrieve word variants: tu sach ty nang ((tai hoi) OR (dai hoi)). hieu van cac dat ((va thanh) or (va dinh)) vi cua vat*.