Perhaps you should try some spelling variations:
dua tren » dung tren
hieu van » hieu va, thien van, lieu va
tu sach » thu sach, su sach, te sach
xuc ban » duc ban, cuc ban, quoc ban
sach ky » sac ky, sach y, sach ty
cau xuc » cam xuc, cau luc, cau truc
van cau » van dau, van hau, van chat
cuu tre » cua tre, cau tren, cau treo
anh vi » hanh vi, anh ve, anh vu
anh va » hanh va
x hoi » xa hoi, o hoi, x ho

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach ky nang x hoi. hieu van cau xuc ban ((anh vi) or (anh va)) ((dua tren) or (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang x hoi. hieu van cau xuc ban ((anh vi) OR (anh va)) ((dua tren) OR (cuu tre)).
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang x hoi. hieu van cau xuc ban ((anh vi) or (anh va)) ((dua tren) or (cuu tre))*.