Perhaps you should try some spelling variations:
cau tren » cu tren, dau tren, ca tren
hieu van » hieu va, thien van, lieu va
va thanh » gia thanh, ban thanh, va tinh
ban hanh » ban hang
van cac » van hac, van cau, van bac
cac duc » cac du, cao duc, cac dac
cau tre » cau treo, cau tra, cuu tre
te sach » toc sach
sach v » sach va, sach y, sach 2
v nang » va nang, vu nang, van nang
x hoi » xa hoi, o hoi, x ho

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

• Performing a fuzzy search may retrieve terms with similar spellings: te sach v nang x hoi. hieu van cac duc ((ban hanh) or (va thanh)) di ((cau tre) OR (cau tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach v nang x hoi. hieu van cac duc ((ban hanh) OR (va thanh)) di ((cau tre) OR (cau tren)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach v nang x hoi. hieu van cac duc ((ban hanh) or (va thanh)) di ((cau tre) OR (cau tren))".
• Adding a wildcard symbol may retrieve word variants: te sach v nang x hoi. hieu van cac duc ((ban hanh) or (va thanh)) di ((cau tre) OR (cau tren))*.