Perhaps you should try some spelling variations:
thao khoa » thai khoa, toan khoa, pham khoa
cham duc » pham duc, cham soc, pham duy
tao khoi » tao hoi, lao khoa, tao boi
van hanh » van thanh, ban hanh, van anh
su sach » so sach, vu sach
lai cua » dai cua, hai cua, lai chau
va hanh » va thanh, va danh, ban hanh
hieu vu » hieu va, hieu ve, hieu su
vu cham » va cham, vu kham, tu cham
sach ty » sach y, sach tu, sach thu
ty sang » ty xang, ty hang, duy sang
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: su sach ty sang ((tao khoi) OR (thao khoa)). hieu vu cham duc ((va hanh) or (van hanh)) lai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ty sang ((tao khoi) OR (thao khoa)). hieu vu cham duc ((va hanh) OR (van hanh)) lai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ty sang ((tao khoi) OR (thao khoa)). hieu vu cham duc ((va hanh) or (van hanh)) lai cua tre".
• Adding a wildcard symbol may retrieve word variants: su sach ty sang ((tao khoi) OR (thao khoa)). hieu vu cham duc ((va hanh) or (van hanh)) lai cua tre*.