Perhaps you should try some spelling variations:
dung thong » dung thuong, dung trong, dong thong
nang quan » ban quan, nang suat
hieu luat » hieu qua
tin nang » ki nang, thi nang, van nang
quan uan » quan luan, quang uan, quan quan
uan hieu » luan hieu, van hieu, luan tieu
quan dan » quan doan, quan den, quan van
dan son » dang son, van son, dai son

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( tin nang quan uan hieu luat ) or ( tin dung thong quan dan son ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tin nang quan uan hieu luat ) OR ( tin dung thong quan dan son ))*.