Perhaps you should try some spelling variations:
xuan tuan » xuan thuan, xuan toan, xuan tan
cham xuan » pham xuan, pham luan, pham tuan
hieu van » thien van, lieu va, hieu ve
so sach » so sanh, bo sach, co sach
sach ky » sac ky, sach y, sach ty
hieu va » lieu va, hieu qua
anh hoi » anh noi, anh hoc, anh khoa
hoi cua » hoi chuc
cua tre » cua te, cuu tre, cua triet
x hoi » xa hoi, o hoi, 5 hoi

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

• Performing a fuzzy search may retrieve terms with similar spellings: so sach ky nang ((x hoi) OR (x ho)). ((hieu van) or (hieu va)) cham xuan tuan anh hoi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach ky nang ((x hoi) OR (x ho)). ((hieu van) OR (hieu va)) cham xuan tuan anh hoi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach ky nang ((x hoi) OR (x ho)). ((hieu van) or (hieu va)) cham xuan tuan anh hoi cua tre".
• Adding a wildcard symbol may retrieve word variants: so sach ky nang ((x hoi) OR (x ho)). ((hieu van) or (hieu va)) cham xuan tuan anh hoi cua tre*.