Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
tai khoi » tai khoa, mai khoi, tao khoi
ban hanh » ban hang
dien cuc » dien tu, dieu cua, vien cac
tai hoi » dai hoi, tai hai, tai hoe
hieu vu » hieu va, hieu ve, hieu su
vu pham » su pham, vi pham, vu kham
va danh » va dinh, va dan, va hanh
cuc tre » duc tre, cua tre, cuu tre
sach v » sach va, sach y, sach 2
v nang » va nang, vu nang, van nang

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: toc sach v nang ((tai hoi) or (tai khoi)). hieu vu pham duc ((va danh) or (ban hanh)) dien cuc tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach v nang ((tai hoi) OR (tai khoi)). hieu vu pham duc ((va danh) OR (ban hanh)) dien cuc tre.
• Adding a wildcard symbol may retrieve word variants: toc sach v nang ((tai hoi) or (tai khoi)). hieu vu pham duc ((va danh) or (ban hanh)) dien cuc tre*.