Perhaps you should try some spelling variations:
sieu viet » su viet, dien viet, bien viet
hieu viec » nhieu viec, hieu ve, hieu hien
dinh toi » dinh tri, dinh thi, dinh moi
cac nuoc » cap nuoc, hoc nuoc, dat nuoc
hieu va » lieu va, hieu qua
toi cua » troi cua, tri cua, hoi cua
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
ky lang » ky nang, ky dang, ky tang
cua tre » cua te, cuu tre, cua triet

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 lang xa hoi. ((((hieu viec) OR (sieu viet))) or (hieu va)) cac nuoc va dinh toi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky lang xa hoi. ((((hieu viec) OR (sieu viet))) OR (hieu va)) cac nuoc va dinh toi cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky lang xa hoi. ((((hieu viec) OR (sieu viet))) or (hieu va)) cac nuoc va dinh toi cua tre*".