Perhaps you should try some spelling variations:
hieu hien » bieu hien, dieu hien, chieu chien
hien cac » thien cac, vien cac, hieu cac
dinh vai » dinh van, dinh vi, dinh va
cua viet » ca viet, hoa viet, cua vat
su sach » so sach, vu 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
cac lao » ca lao, cac loai, cac giao
va dinh » van dinh, va kinh, va tinh
cua tre » cua te, cuu tre, cua triet
ma hoi » mai hoi, xa hoi, ma hoa
lao va » tao va, cao va, bao va

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: su sach ty nang ma hoi. hieu hien cac lao va dinh vai ((cua tre) or (cua viet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ty nang ma hoi. hieu hien cac lao va dinh vai ((cua tre) OR (cua viet)).
• Adding a wildcard symbol may retrieve word variants: su sach ty nang ma hoi. hieu hien cac lao va dinh vai ((cua tre) or (cua viet))*.