Perhaps you should try some spelling variations:
day thanh » dao thanh, dat thanh, da thanh
thanh doi » thanh loi, thanh moi, thanh do
toc sach » hoc sach, doc sach, thuoc sach
hieu van » hieu va, thien van, lieu va
nam thuc » nam thuoc, am thuc, nam tu
sach ty » sach y, sach tu, sach thu
ty nang » ky nang, ty xang, ty hang
nang ma » tang ma, sang ma, nang cao
doi cua » dai cua, hoi 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: toc sach ty nang ma hoi. hieu van ((nam thuc) or (nam thu)) day thanh doi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ty nang ma hoi. hieu van ((nam thuc) OR (nam thu)) day thanh doi cua tre.
• Adding a wildcard symbol may retrieve word variants: toc sach ty nang ma hoi. hieu van ((nam thuc) or (nam thu)) day thanh doi cua tre*.