Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
hieu van » hieu va, thien van, lieu va
va thanh » gia thanh, ban thanh, va tinh
sach ky » sac ky, sach y, sach ty
van hac » van hoc, van ha, van hai
hac dat » hoc dat, tac dat, hoach dat
vai cua » dai cua, hai cua, lai cua
ma hoi » mai hoi, ma hoa, me hoi
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 sach ky nang ((ma hoi) or (xa hoi)). hieu van hac dat va thanh ((vi cua) OR (vai cua)) vat~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ky nang ((ma hoi) OR (xa hoi)). hieu van hac dat va thanh ((vi cua) OR (vai cua)) vat.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ky nang ((ma hoi) or (xa hoi)). hieu van hac dat va thanh ((vi cua) OR (vai cua)) vat".
• Adding a wildcard symbol may retrieve word variants: thu sach ky nang ((ma hoi) or (xa hoi)). hieu van hac dat va thanh ((vi cua) OR (vai cua)) vat*.