Perhaps you should try some spelling variations:
nang cau » nang cao, hang cau, nang dau
thanh de » hanh de, thanh ve, thanh le
thanh do » thanh pho, thanh hoa, thanh loi
tu sach » thu sach, su sach, te sach
hieu ve » hieu van
hieu va » lieu va, hieu qua
cuu tre » cua tre, cau tren, cau treo
y nang » ky nang, ly nang, v nang
du va » dau va, tu va, su va

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 y nang cau hoi. ((hieu ve) OR (hieu va)) cac du va ((thanh de) or (thanh do)) cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y nang cau hoi. ((hieu ve) OR (hieu va)) cac du va ((thanh de) OR (thanh do)) cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach y nang cau hoi. ((hieu ve) OR (hieu va)) cac du va ((thanh de) or (thanh do)) cuu tre".
• Adding a wildcard symbol may retrieve word variants: tu sach y nang cau hoi. ((hieu ve) OR (hieu va)) cac du va ((thanh de) or (thanh do)) cuu tre*.