Perhaps you should try some spelling variations:
thanh dai » thanh hai, thanh tai, thanh dat
ban thanh » ban hanh, ban hang
hieu van » thien van, hieu ve
vu sach » vu bach, su sach, vu khach
sach ky » sac ky, sach y, sach ty
cao hoi » cau hoi, co hoi, cao hoc
hieu va » hieu qua
cac qua » cau qua, tac quan
qua ban » cua ban, qua quan
cua tre » cua te, cuu tre, cua triet

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 ky nang cao hoi. ((((hieu van) or (lieu va))) or (hieu va)) cac qua ban thanh dai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu sach ky nang cao hoi. ((((hieu van) OR (lieu va))) OR (hieu va)) cac qua ban thanh dai cua tre.
• Adding a wildcard symbol may retrieve word variants: vu sach ky nang cao hoi. ((((hieu van) or (lieu va))) or (hieu va)) cac qua ban thanh dai cua tre*.