Perhaps you should try some spelling variations:
thanh hai » thanh phan, thanh hoa, thanh san
ban thanh » ban hanh, ban hang
hieu van » hieu va, thien van, lieu va
su sach » so sach, vu sach
duc ban » duc tan, duc van, dua ban
cua tre » cua te, cua triet, dua tren
lam duc » lam duoc, pham duc, nam duoc
van lam » van nam
ky tang » ky dang, kho tang, ky trong
cuu tre » cau tren, cau treo

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 tang) or (ky nang)) xa hoi. hieu van lam duc ban thanh hai ((cua tre) or (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ((ky tang) OR (ky nang)) xa hoi. hieu van lam duc ban thanh hai ((cua tre) OR (cuu tre)).
• Adding a wildcard symbol may retrieve word variants: su sach ((ky tang) or (ky nang)) xa hoi. hieu van lam duc ban thanh hai ((cua tre) or (cuu tre))*.