Perhaps you should try some spelling variations:
thanh hoa » thanh pho
hieu van » hieu va, thien van, lieu va
cua tre » cua te, cuu tre, cua triet
hoa cua » hoa chat, hoa xuat
van lam » van nam
tang xa » trang xa, tang ma, lang xa
ky tang » ky nang, ky dang, kho tang
su sach » so sach, vu sach
xuc va » duc va, tuc va, xac va
luc va » duc va, tuc va, loc va
su sac » su cac, su xac

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

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