Perhaps you should try some spelling variations:
cau treo » cau theo, cau tren, cau triet
va thanh » gia thanh, ban thanh, va tinh
nang cau » nang cao, hang cau, nang dau
thanh di » thanh doi, thanh de, thanh do
cau tre » cau tren, cau tra, cuu tre
tu sach » thu sach, su sach, te sach
hieu ve » hieu va, hieu van
cac duc » cao duc, cac dac, cac nuoc
y nang » ky nang, ly nang, v nang

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