Perhaps you should try some spelling variations:
nhung duong » nhung dung, nhung huong, nhung tuong
duong minh » duong manh, truong minh, thong minh
minh tuan » anh tuan
doc hieu » toc thieu, hoc thieu, hoc hien
hieu luc » hieu luat, hieu qua
tranh va » tranh van, trang va, trinh va
tuan cao » toan cao, juan cao, quang cao

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 luc - (canh or hanh) tranh va nhung duong minh tuan cao~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc hieu luc - (canh OR hanh) tranh va nhung duong minh tuan cao.
• Adding a wildcard symbol may retrieve word variants: doc hieu luc - (canh or hanh) tranh va nhung duong minh tuan cao*.