Perhaps you should try some spelling variations:
thanh va » thanh van, hanh va, thanh ha
hieu van » thien van, lieu va, hieu ve
thanh ve » hanh ve, thanh vien, thanh van
su sach » so sach, vu sach
hai cuc » tai cuc, hai cua, thai cua
sach ky » sac ky, sach y, sach ty
hieu va » lieu va, hieu qua
nang xa » nang x, lang xa, nang ma
cua tre » cua te, cuu tre, cua triet
cuc va » chuc va, duc va, cuu va

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