Perhaps you should try some spelling variations:
thu sach » thuat sach, thuoc sach, thu hoach
hanh hai » thanh hai, nhanh hai, hang hai
sang tay » sang tao, sang tai, sang tac
tu sach » su sach, te sach, tu cach
hieu so » thieu so
hai cua » thai cua, dai cua, hoi cua
va hanh » van hanh, va thanh, va danh
hieu su » hieu sau, tieu su, hieu suat
tay hoi » tay ho, tao hoi, tay thai
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: ((tu sach) or (thu sach)) ty sang tay hoi. ((hieu su) or (hieu so)) pham duc va hanh hai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (thu sach)) ty sang tay hoi. ((hieu su) OR (hieu so)) pham duc va hanh hai cua tre.
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (thu sach)) ty sang tay hoi. ((hieu su) or (hieu so)) pham duc va hanh hai cua tre*.