Perhaps you should try some spelling variations:
tang hanh » tang thanh, dang hanh, nang hanh
hieu van » hieu va, thien van, lieu va
duc tang » duc thang, duc tan, tuc tang
hanh dai » hanh tai, hanh dao, vanh dai
sach ty » sach y, sach tu, sach thu
nang ma » tang ma, sang ma, nang cao
van cam » van nam, van lam, van cau
cam duc » cam xuc, cao duc, pham duc
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) or (cac ky)) nang ma hoi. hieu van cam duc tang hanh dai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach ty) OR (cac ky)) nang ma hoi. hieu van cam duc tang hanh dai cua tre.
• Adding a wildcard symbol may retrieve word variants: tu ((sach ty) or (cac ky)) nang ma hoi. hieu van cam duc tang hanh dai cua tre*.