Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
tai khoi » tai khoa, mai khoi, tao khoi
dien cua » dieu cua, dien cuc, dien cu
tai hoe » tai he, tai khoa, thai hoc
hieu vu » hieu va, hieu ve, hieu su
vu pham » su pham, vi pham, vu kham
va danh » va dinh, va dan, dia danh
va hanh » van hanh, va thanh, ban hanh
cua tre » cua te, cuu tre, cua triet
y nang » ky nang, ly nang, v 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 y nang ((tai hoe) or (tai khoi)). hieu vu pham duc ((va danh) or (va hanh)) dien cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach y nang ((tai hoe) OR (tai khoi)). hieu vu pham duc ((va danh) OR (va hanh)) dien cua tre.
• Adding a wildcard symbol may retrieve word variants: toc sach y nang ((tai hoe) or (tai khoi)). hieu vu pham duc ((va danh) or (va hanh)) dien cua tre*.