Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
thanh vai » thanh hai, thanh van, thanh tai
van hieu » cao hieu
cua viet » ca viet, hoa viet, cua vat
su sach » so sach, vu sach
van hoe » van hoa, van hoc, van hien
hieu ve » hieu va, hieu van
cac cuc » cac cuoc, cac cua, cac nuoc
cuc ban » cua ban, cac ban, cuu ban
vai cua » dai cua, hai cua, lai cua
y tang » ky tang, 6 tang, 7 tang
ve cac » va cac, vien cac

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 y tang ((van hoe) or (van hieu)). hieu ve cac cuc ban thanh vai cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach y tang ((van hoe) OR (van hieu)). hieu ve cac cuc ban thanh vai cua viet.
• Adding a wildcard symbol may retrieve word variants: su sach y tang ((van hoe) or (van hieu)). hieu ve cac cuc ban thanh vai cua viet*.