Perhaps you should try some spelling variations:
chay tren » thai tren, ca tren, cau tren
hieu van » hieu va, thien van, lieu va
chau tre » chau tho, cho tre, cau tra
ban hanh » ban hang
thu sach » tu sach, thuat sach, thuoc sach
hieu ve » hieu va
sach ty » sach y, sach tu, sach thu
cac duc » cac du, cao duc, cac dac
duc ban » duc tan, duc van, dua ban
hanh va » hang va, hanh vi
ty nang » ky nang, ty xang, ty hang
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: thu sach ty nang x hoi. ((hieu ve) OR (hieu van)) cac duc ban hanh va ((chau tre) or (chay tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ty nang x hoi. ((hieu ve) OR (hieu van)) cac duc ban hanh va ((chau tre) OR (chay tren)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ty nang x hoi. ((hieu ve) OR (hieu van)) cac duc ban hanh va ((chau tre) or (chay tren))".
• Adding a wildcard symbol may retrieve word variants: thu sach ty nang x hoi. ((hieu ve) OR (hieu van)) cac duc ban hanh va ((chau tre) or (chay tren))*.