Perhaps you should try some spelling variations:
cau thuc » cau truc, cuu thuc, can thuc
vat hanh » vat thanh, van hanh, va hanh
hanh tai » thanh tai, hang tai, han tai
tu sach » thu sach, su sach, te sach
sach ty » sach y, sach tu, sach thu
ty nang » ky nang, ty xang, ty hang
nang ma » tang ma, sang ma, nang cao
hieu ve » hieu van
hieu va » lieu va, hieu qua
tai cua » thai cua, tai cuc, tri cua
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 ty nang ma hoi. ((hieu ve) or (hieu va)) cau thuc vat hanh tai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty nang ma hoi. ((hieu ve) OR (hieu va)) cau thuc vat hanh tai cua tre*.