Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
thanh tai » thanh hai, thanh toan, doanh tai
hieu van » hieu va, thien van, lieu va
tu sach » thu sach, su sach, te sach
cao hoc » co hoc, cho hoc, chat hoc
van cac » van hac, van cau, van bac
cac cuc » cac cuoc, cac cua, cac nuoc
cuc ban » cua ban, cac ban, cuu ban
buu tre » cuu tre

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) or (thu hoach)) ky nang cao hoc. hieu van cac cuc ban thanh tai buu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (thu hoach)) ky nang cao hoc. hieu van cac cuc ban thanh tai buu tre.
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (thu hoach)) ky nang cao hoc. hieu van cac cuc ban thanh tai buu tre*.