Perhaps you should try some spelling variations:
tru nang » tra nang, tri nang, thi nang
hieu van » hieu va, thien van, lieu va
tu sach » thu sach, su sach, te sach
hanh di » hanh vi, hanh de, hang di
cuu ban » cuu van, cua ban, cuu san
cuc ban » cua ban, cac ban, duc ban
van cam » van nam, van lam, van cau
cuu tre » cua tre, cau tren, cau treo
di cuu » di cau, di cua, dinh cuu

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 ((tru nang) or (truc nano)) xa hoi. hieu van cam ((cuc ban) OR (cuu ban)) hanh di cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((tru nang) OR (truc nano)) xa hoi. hieu van cam ((cuc ban) OR (cuu ban)) hanh di cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((tru nang) or (truc nano)) xa hoi. hieu van cam ((cuc ban) OR (cuu ban)) hanh di cuu tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ((tru nang) or (truc nano)) xa hoi. hieu van cam ((cuc ban) OR (cuu ban)) hanh di cuu tre*.