Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
hanh dai » hanh tai, hanh dao, vanh dai
bo sach » co sach, hoc sach
sach tu » sach thu, cach tu, sach ty
tu nano » truc nano
hieu ve » hieu van
hieu va » lieu va, hieu qua
cam duc » cam xuc, cao duc, pham duc
duc van » duc va, duc tan, duc manh
nano o » nano 1, nano cuo, nano mot
cua te » cua tu
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: bo sach tu nano o hoi. ((hieu ve) or (hieu va)) cam duc van hanh dai cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: bo sach tu nano o hoi. ((hieu ve) OR (hieu va)) cam duc van hanh dai cua te*.