Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
sach ky » sac ky, sach y, sach ty
dinh vi » dinh ve, dinh viet, dinh tri
danh vi » hanh vi, danh di, danh va
hac tuc » thac toc, thai tuc
cuu tre » cua tre, cau tren, cau treo
hieu va » lieu va, hieu qua
tuc va » thuc va, truc va, tuc xa
va hac » van hac, va khac, va cac
o hoi » co hoi, o hoc, o hai
x hoi » xa hoi, x ho, 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: thu sach ky nang ((x hoi) or (o hoi)). hieu va hac tuc va ((danh vi) OR (dinh vi)) cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ky nang ((x hoi) OR (o hoi)). hieu va hac tuc va ((danh vi) OR (dinh vi)) cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ky nang ((x hoi) or (o hoi)). hieu va hac tuc va ((danh vi) OR (dinh vi)) cuu tre".
• Adding a wildcard symbol may retrieve word variants: thu sach ky nang ((x hoi) or (o hoi)). hieu va hac tuc va ((danh vi) OR (dinh vi)) cuu tre*.