Perhaps you should try some spelling variations:
thu sach » thuat sach, thuoc sach, thu hoach
hanh tai » thanh tai, hang tai, han tai
cham duc » pham duc, cham soc, pham duy
tu sach » su sach, te sach, tu cach
tai cua » thai cua, tai cuc, tri cua
va hanh » van hanh, va thanh, va danh
vu cham » va cham, vu kham, tu cham
hieu vu » hieu va, hieu ve, hieu su
tao hoi » tao khoi, tao boi, tay hoi
ty sang » ty hang, duy sang, thu 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: ((tu sach) or (thu sach)) ((ty sang) OR (ty xang)) tao hoi. hieu vu cham duc va hanh tai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (thu sach)) ((ty sang) OR (ty xang)) tao hoi. hieu vu cham duc va hanh tai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (thu sach)) ((ty sang) OR (ty xang)) tao hoi. hieu vu cham duc va hanh tai cua tre".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (thu sach)) ((ty sang) OR (ty xang)) tao hoi. hieu vu cham duc va hanh tai cua tre*.