Perhaps you should try some spelling variations:
hieu vien » hieu hien, hieu viec, thieu nien
kho tang » cao tang
dinh vai » dinh van, dinh vi, dinh va
bach tao » bach mao, bach giao, bach tuoc
tu sach » thu sach, te sach, tu cach
vai cua » dai cua, hai cua, lai cua
va dinh » van dinh, va kinh, va tinh
ky tang » ky nang, ky dang, ky trong
su sach » so sach, vu sach
cua tre » cua te, cuu tre, cua triet
ma hoi » mai hoi, xa hoi, ma hoa

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((tu sach) or (su sach)) ((ky tang) OR (kho tang)) ma hoi. hieu vien bach tao va dinh vai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (su sach)) ((ky tang) OR (kho tang)) ma hoi. hieu vien bach tao va dinh vai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (su sach)) ((ky tang) OR (kho tang)) ma hoi. hieu vien bach tao va dinh vai cua tre".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (su sach)) ((ky tang) OR (kho tang)) ma hoi. hieu vien bach tao va dinh vai cua tre*.