Perhaps you should try some spelling variations:
hieu thien » hieu hien, chieu chien, dieu khien
thien cac » hien cac, thien cau, thieu cac
su triet » su viet, su tien, ve triet
dinh vai » dinh van, dinh vi, dinh va
cua tre » cua te, cuu tre, cua triet
va dinh » van dinh, va kinh, va tinh
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
lang xa » lang ha, dang xay, lang van
nang xa » nang x, nang ma, mang xa
cac lo » cac lop, cac co, cac bo
lo va » lo van, lao va, ly 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 ky ((nang xa) OR (lang xa)) hoi. hieu thien cac lo va dinh vai ((cua tre) or (su triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky ((nang xa) OR (lang xa)) hoi. hieu thien cac lo va dinh vai ((cua tre) OR (su triet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky ((nang xa) OR (lang xa)) hoi. hieu thien cac lo va dinh vai ((cua tre) or (su triet))".
• Adding a wildcard symbol may retrieve word variants: su sach ky ((nang xa) OR (lang xa)) hoi. hieu thien cac lo va dinh vai ((cua tre) or (su triet))*.