Perhaps you should try some spelling variations:
nhung cong » dung cong, thong cong, hang cong
tuong cua » truong cua, huong cua, thong cua
hang nong » thang long, han tong
hoc hieu » hoc thieu, hoc hien, doc hieu
hieu luc » hieu luat, hieu qua
tung cua » trung cua, dung cua, tang cua
dan toan » van toan, dan than, manh toan
toan cau » toan cao, toan ban, toan tap

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc hieu luc - thanh ((tung cua) OR (tuong cua)) ((nhung cong) or (hang nong)) dan toan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc hieu luc - thanh ((tung cua) OR (tuong cua)) ((nhung cong) OR (hang nong)) dan toan cau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc hieu luc - thanh ((tung cua) OR (tuong cua)) ((nhung cong) or (hang nong)) dan toan cau".
• Adding a wildcard symbol may retrieve word variants: hoc hieu luc - thanh ((tung cua) OR (tuong cua)) ((nhung cong) or (hang nong)) dan toan cau*.