Perhaps you should try some spelling variations:
thanh hai » thanh phan, thanh hoa, thanh san
kho tang » cao tang
ky tang » ky nang, ky dang, ky trong
qua cac » cua cac
luc van » luoc van, duc van, luc va
luu van » cuu van, luan van, luu hanh
hai cua » thai cua, dai cua, hoi cua
cua tre » cua te, cuu tre, cua triet
su cac » tu cac, su cao, su can

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

• Performing a fuzzy search may retrieve terms with similar spellings: su cac ((ky tang) or (kho tang)) xa hoi. hieu qua cac ((luc van) OR (luu van)) thanh hai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su cac ((ky tang) OR (kho tang)) xa hoi. hieu qua cac ((luc van) OR (luu van)) thanh hai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su cac ((ky tang) or (kho tang)) xa hoi. hieu qua cac ((luc van) OR (luu van)) thanh hai cua tre".
• Adding a wildcard symbol may retrieve word variants: su cac ((ky tang) or (kho tang)) xa hoi. hieu qua cac ((luc van) OR (luu van)) thanh hai cua tre*.