Perhaps you should try some spelling variations:
hieu van » thien van, lieu va, hieu ve
va thanh » gia thanh, ban thanh, va tinh
thanh va » thanh van, hanh va, thanh ha
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
ky tang » ky nang, ky dang, kho tang
tang xa » trang xa, tang ma, lang xa
hieu va » lieu va, hieu qua
truc va » thuc va, thuc vat, trung va
cua tre » cua te, cuu tre, cua triet

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

• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky tang xa hoi. ((hieu van) OR (hieu va)) cau truc va thanh va ((cua tre) OR (cua vat))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky tang xa hoi. ((hieu van) OR (hieu va)) cau truc va thanh va ((cua tre) or (cua vat))~".
• Adding a wildcard symbol may retrieve word variants: su sach ky tang xa hoi. ((hieu van) OR (hieu va)) cau truc va thanh va ((cua tre) or (cua vat))*.