Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
tu sach » thu sach, su sach, te sach
cao hoc » co hoc, cho hoc, chat hoc
van hac » van hoc, van ha, van hai
hac dac » cac dac, ha dac, nhac dan
va hanh » van hanh, va thanh, va danh
y nang » ly nang, v nang, may nang
dac va » duc va, day va, dat va
vi cua » vai cua
di cua » dai cua, doi cua, de cua

You may be able to get more results by adjusting your search query.

• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((y nang) OR (ky nang)) cao hoc. hieu van hac dac va hanh ((vi cua) OR (di cua)) viet~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((y nang) OR (ky nang)) cao hoc. hieu van hac dac va hanh ((vi cua) or (di cua)) viet~".
• Adding a wildcard symbol may retrieve word variants: tu sach ((y nang) OR (ky nang)) cao hoc. hieu van hac dac va hanh ((vi cua) or (di cua)) viet*.