Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
hieu van » hieu va, thien van, lieu va
van phan » van phong, van thanh, luan phan
phan day » phan dau, phap day, phan xay
hanh lai » hanh tai, thanh lap, thanh loi
hanh lam » thanh lap, hanh kem, hanh va
sach ty » sach y, sach tu, sach thu
ty nang » ky nang, ty xang, ty hang
nang ma » tang ma, sang ma, nang cao
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 phan day va ((hanh lai) or (hanh lam)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ty nang ma hoi. hieu van phan day va ((hanh lai) OR (hanh lam)) cua tre.
• Adding a wildcard symbol may retrieve word variants: toc sach ty nang ma hoi. hieu van phan day va ((hanh lai) or (hanh lam)) cua tre*.