Perhaps you should try some spelling variations:
dau tren » dau tien, dat tren, dau tieng
nang cau » nang cao, hang cau, bang cau
cau tren » cu tren, ca tren, cau treo
nang dau » hang dau, xang dau, nang du
cau luc » cau truc, cau phuc
dinh vi » dinh ve, dinh viet, dinh tri
va dinh » van dinh, va kinh, va tinh
hoc anh » hoc nganh, hoc nhanh, ngoc anh
hieu ve » hieu va, hieu van
anh ky » hanh ky, anh y, anh my
luc va » duc va, tuc va, loc va
ve cau » ke cau, va cau, ve cac

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: hoc anh ky ((nang cau) OR (nang dau)) hoi. hieu ve cau luc va dinh vi ((cau tren) or (dau tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc anh ky ((nang cau) OR (nang dau)) hoi. hieu ve cau luc va dinh vi ((cau tren) OR (dau tren)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc anh ky ((nang cau) OR (nang dau)) hoi. hieu ve cau luc va dinh vi ((cau tren) or (dau tren))".
• Adding a wildcard symbol may retrieve word variants: hoc anh ky ((nang cau) OR (nang dau)) hoi. hieu ve cau luc va dinh vi ((cau tren) or (dau tren))*.