Perhaps you should try some spelling variations:
cau tren » cu tren, dau tren, ca tren
van hanh » van thanh, ban hanh, van anh
truc van » truc va, thuc van, truc ban
cam truc » cau truc, nam truc, lam truoc
hieu va » lieu va, hieu qua
sach va » sach xa, sach ha, sach dao
va nang » van nang, da nang, cam nang
hanh de » hanh ve, hanh kem
cua tre » cua te, cuu tre, cua triet
vu sach » vu bach, su sach, vu khach
va cam » va cham, va cac, va cao
nang o » nang co, nang ho, nang ro
o hoi » co hoi, o hoc, o hai

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

• Performing a fuzzy search may retrieve terms with similar spellings: vu sach va nang o hoi. hieu va cam truc van hanh de ((cua tre) or (cau tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu sach va nang o hoi. hieu va cam truc van hanh de ((cua tre) OR (cau tren)).
• Adding a wildcard symbol may retrieve word variants: vu sach va nang o hoi. hieu va cam truc van hanh de ((cua tre) or (cau tren))*.