Perhaps you should try some spelling variations:
khanh toan » thanh toan, khanh thanh, khanh thuan
van khanh » van thanh, van hanh, van anh
ban tren » ban tre, van tren, ban ren
toan ban » van ban
sach ky » sac ky, sach y, sach ty
hieu ve » hieu va, hieu van
cac xuc » cam xuc, cac nuoc, chat xuc
xuc van » duc van, luc van, vuc van
tu sach » thu sach, su sach, te sach
mo hoc » mon hoc, co hoc
co hai » co dai, co hoi, o hai
ve cac » va cac, vien cac
o hoc » co hoc, so hoc, y hoc

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 ((((o hoc) OR (mo hoc))) or (co hai)). hieu ve cac xuc van khanh toan ban tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang ((((o hoc) OR (mo hoc))) OR (co hai)). hieu ve cac xuc van khanh toan ban tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky nang ((((o hoc) OR (mo hoc))) or (co hai)). hieu ve cac xuc van khanh toan ban tren".
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang ((((o hoc) OR (mo hoc))) or (co hai)). hieu ve cac xuc van khanh toan ban tren*.