Perhaps you should try some spelling variations:
sang thao » sang tao, sang than, rang thao
thao khoa » thai khoa, toan khoa, pham khoa
cham duc » pham duc, cham soc, pham duy
van hanh » van thanh, ban hanh, van anh
su sach » so sach, vu sach
sach ty » sach y, sach tu, sach thu
ty sang » ty xang, ty hang, duy sang
hieu tu » chieu tu, hieu tuc, hien tu
tu cham » toc cham, thi cham
va hanh » va thanh, va danh, ban hanh
lai cua » dai cua, hai cua, lai chau
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 thao khoa. hieu tu 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 thao khoa. hieu tu cham duc ((va hanh) OR (van hanh)) lai cua tre.
• Adding a wildcard symbol may retrieve word variants: su sach ty sang thao khoa. hieu tu cham duc ((va hanh) or (van hanh)) lai cua tre*.