Perhaps you should try some spelling variations:
cau tren » cu tren, ca tren, cau treo
dau tren » dau tien, dat tren, dau tieng
hoc anh » hoc nganh, hoc nhanh, ngoc anh
cao hoi » cau hoi, co hoi, cao hoc
hieu ve » hieu van
hieu va » lieu va, hieu qua
truc va » thuc va, thuc vat, trung va
va dinh » van dinh, va kinh, va tinh
dinh vi » dinh ve, dinh viet, dinh tri
anh ky » hanh ky, anh y, anh my

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 cao hoi. ((hieu ve) OR (hieu va)) cau truc 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 cao hoi. ((hieu ve) OR (hieu va)) cau truc 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 cao hoi. ((hieu ve) OR (hieu va)) cau truc va dinh vi ((cau tren) or (dau tren))".
• Adding a wildcard symbol may retrieve word variants: hoc anh ky nang cao hoi. ((hieu ve) OR (hieu va)) cau truc va dinh vi ((cau tren) or (dau tren))*.