Perhaps you should try some spelling variations:
sach tru » sach truc, sach thu, sach tu
tru nang » tra nang, tri nang, truc nano
tan hanh » tan thanh, tang hanh, toan hanh
hanh lam » thanh lap, hanh kem, hanh va
tu sach » thu sach, su sach, te sach
hieu ve » hieu va, hieu van
ve pham » vi pham, v pham, ve phan
cua tre » cuu tre, cua triet, dua tren
cua te » cua tu
x hoi » xa hoi, o hoi, 5 hoi

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 tru nang ((x hoi) or (x ho)). hieu ve pham duc tan hanh lam ((cua tre) or (cua te))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach tru nang ((x hoi) OR (x ho)). hieu ve pham duc tan hanh lam ((cua tre) OR (cua te)).
• Adding a wildcard symbol may retrieve word variants: tu sach tru nang ((x hoi) or (x ho)). hieu ve pham duc tan hanh lam ((cua tre) or (cua te))*.