Perhaps you should try some spelling variations:
cau tren » cu tren, dau tren, ca tren
thu lang » thu hang, thu bang, phu lang
cau treo » cau theo, cau triet, cau trieu
gia hanh » gia thanh, giao hanh, gia anh
hanh ke » hanh kem, thanh ke, hanh ky
duc gia » quoc gia
tu sach » thu sach, su sach, te sach
hieu ve » hieu va, hieu van
cac duc » cac du, cao duc, cac dac
ve cac » va cac, vien cac

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 ((thu lang) or (thuc hanh)) xa hoi. hieu ve cac duc gia hanh ke ((cau treo) OR (cau tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((thu lang) OR (thuc hanh)) xa hoi. hieu ve cac duc gia hanh ke ((cau treo) OR (cau tren)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((thu lang) or (thuc hanh)) xa hoi. hieu ve cac duc gia hanh ke ((cau treo) OR (cau tren))".
• Adding a wildcard symbol may retrieve word variants: tu sach ((thu lang) or (thuc hanh)) xa hoi. hieu ve cac duc gia hanh ke ((cau treo) OR (cau tren))*.