Perhaps you should try some spelling variations:
cau tren » cu tren, dau tren, ca tren
thu lang » thu hang, thu bang, phu lang
thanh vi » hanh vi, thanh va, thanh ve
cao duc » dao duc, cao suc, giao duc
cac duc » cac du, cac dac, cac nuoc
su sach » so sach, vu sach
hieu ve » hieu va, hieu van
thu ban » thu hang
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: su sach ((thu lang) or (thu ban)) xa hoi. hieu ve ((cac duc) OR (cao duc)) gia thanh vi cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ((thu lang) OR (thu ban)) xa hoi. hieu ve ((cac duc) OR (cao duc)) gia thanh vi cau tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ((thu lang) or (thu ban)) xa hoi. hieu ve ((cac duc) OR (cao duc)) gia thanh vi cau tren".
• Adding a wildcard symbol may retrieve word variants: su sach ((thu lang) or (thu ban)) xa hoi. hieu ve ((cac duc) OR (cao duc)) gia thanh vi cau tren*.