Perhaps you should try some spelling variations:
hieu hien » bieu hien, dieu hien, chieu chien
su triet » su viet, su tien, ve triet
van dinh » van minh, van dich, va dinh
dinh vai » dinh van, dinh vi, dinh va
hien cac » thien cac, vien cac, hieu cac
cua tre » cua te, cuu tre, cua triet
su sach » so sach, vu sach
sach ty » sach y, sach tu, sach thu
nang ma » tang ma, sang ma, nang cao
ty nang » ky nang, ty xang, ty hang
lo van » le van, vo van, so van
ma hoi » mai hoi, xa hoi, ma hoa
cac lo » cac lop, cac co, cac bo

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 lo van dinh vai ((cua tre) or (su triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ty nang ma hoi. hieu hien cac lo van dinh vai ((cua tre) OR (su triet)).
• Adding a wildcard symbol may retrieve word variants: su sach ty nang ma hoi. hieu hien cac lo van dinh vai ((cua tre) or (su triet))*.