Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
hanh hai » thanh hai, nhanh hai, hang hai
thu ban » thu hang
nang ma » tang ma, sang ma, nang cao
hieu va » lieu va
va hanh » van hanh, va thanh, va danh
cua tre » cua te, cuu tre, dua tren
ban ky » van ky, dan ky
ma hoi » mai hoi, xa hoi, ma hoa
cac ly » cac ky, cac le, cam ly

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

• Performing a fuzzy search may retrieve terms with similar spellings: thu ban ky nang ma hoi. ((hieu va) or (hieu qua)) cac ly va hanh hai ((cua tre) OR (cua triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu ban ky nang ma hoi. ((hieu va) OR (hieu qua)) cac ly va hanh hai ((cua tre) OR (cua triet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu ban ky nang ma hoi. ((hieu va) or (hieu qua)) cac ly va hanh hai ((cua tre) OR (cua triet))".
• Adding a wildcard symbol may retrieve word variants: thu ban ky nang ma hoi. ((hieu va) or (hieu qua)) cac ly va hanh hai ((cua tre) OR (cua triet))*.