Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
thanh vi » hanh vi, thanh ve, nhanh vi
thanh va » thanh van, hanh va, thanh ha
sach ky » sac ky, sach y, sach ty
nang xa » nang x, lang xa, nang ma
hieu va » lieu va
cao duc » dao duc, cao suc, giao duc
cua tre » cua te, cuu tre, cua triet

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