Perhaps you should try some spelling variations:
cau tren » cu tren, dau tren, ca tren
hanh ve » hanh va, hanh kem
cao duc » dao duc, cao suc, giao duc
su sach » so sach, vu sach
ty nang » ky nang, ty hang, ly nang
hieu ve » hieu va, hieu van
ve cao » va cao, ve bao, ve cac
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: su sach ((ty nang) OR (ty xang)) x hoi. hieu ve cao duc va ((hanh ve) or (hanh vi)) cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ((ty nang) OR (ty xang)) x hoi. hieu ve cao duc va ((hanh ve) OR (hanh vi)) cau tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ((ty nang) OR (ty xang)) x hoi. hieu ve cao duc va ((hanh ve) or (hanh vi)) cau tren".
• Adding a wildcard symbol may retrieve word variants: su sach ((ty nang) OR (ty xang)) x hoi. hieu ve cao duc va ((hanh ve) or (hanh vi)) cau tren*.