Perhaps you should try some spelling variations:
hoc bang » hoc bong, hoc tang, hoc dan
cau tren » cu tren, dau tren, ca tren
bach ky » bac ky
ky lang » ky nang, ky dang, ky tang
lang xa » lang ha, dang xay, lang van
qua cao » qua cac, qua ca, qua cai
coc ban » co ban, cac ban, hoc ban
vi cau » va cau, ve cau, di cau

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

• Performing a fuzzy search may retrieve terms with similar spellings: vu bach ky lang xa hoi. hieu qua cao ((hoc bang) or (coc ban)) hanh vi cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu bach ky lang xa hoi. hieu qua cao ((hoc bang) OR (coc ban)) hanh vi cau tren.
• Adding a wildcard symbol may retrieve word variants: vu bach ky lang xa hoi. hieu qua cao ((hoc bang) or (coc ban)) hanh vi cau tren*.