Perhaps you should try some spelling variations:
thanh dai » thanh hai, thanh tai, thanh dat
hieu van » hieu va, thien van, lieu va
thuc gia » thuc giai, thue gia, thuc dia
su sach » so sach
vu sach » vu bach, vu khach
van am » van nam, van lam, van dam
cua te » cua tu
o hoi » co hoi, o hai, o hoa
o hoc » co hoc, mo hoc, so hoc

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) or (vu sach)) ky nang ((o hoi) or (o hoc)). hieu van am thuc gia thanh dai cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sach) OR (vu sach)) ky nang ((o hoi) OR (o hoc)). hieu van am thuc gia thanh dai cua te.
• Adding a wildcard symbol may retrieve word variants: ((su sach) or (vu sach)) ky nang ((o hoi) or (o hoc)). hieu van am thuc gia thanh dai cua te*.