Perhaps you should try some spelling variations:
nhung thong » chung thong, nhung chong, nhung tuong
nhung phong » nhung phuong, nhung chong, nung phong
hanh tinh » hanh trinh, nhanh tinh, thanh tinh
doc hieu » toc thieu, hoc thieu
tinh cua » trinh cua, sinh cua, tinh chat
san chat » van chat, san chay, ban chat
chat cao » chat co, chat cho, chat bao

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((doc hieu) or (hoc hien)) manh - hanh tinh cua ((nhung thong) OR (nhung phong)) san chat cao~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((doc hieu) OR (hoc hien)) manh - hanh tinh cua ((nhung thong) OR (nhung phong)) san chat cao.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((doc hieu) or (hoc hien)) manh - hanh tinh cua ((nhung thong) OR (nhung phong)) san chat cao".
• Adding a wildcard symbol may retrieve word variants: ((doc hieu) or (hoc hien)) manh - hanh tinh cua ((nhung thong) OR (nhung phong)) san chat cao*.