Perhaps you should try some spelling variations:
su sach » so sach, vu sach
cuu tre » cua tre, cau tren, cau treo
cach su » cach tu, hoach su
hieu ve » hieu va, hieu van
ve cach » va cach, ve cac, ve canh
ca tren » cau tren, cu tren, la tren
y nang » ky nang, ly nang, v nang
co hoi » co hoc, co loi
va dao » ca dao
dao ve » bao ve, dap ve, dau ve
o lai » o lao
su va » su van, tu va

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach y nang ((co hoi) or (o lai)). hieu ve cach su va dao ve ((cuu tre) or (ca tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach y nang ((co hoi) OR (o lai)). hieu ve cach su va dao ve ((cuu tre) OR (ca tren)).
• Adding a wildcard symbol may retrieve word variants: su sach y nang ((co hoi) or (o lai)). hieu ve cach su va dao ve ((cuu tre) or (ca tren))*.