Perhaps you should try some spelling variations:
nhanh mang » nhanh lang, hanh mang, nhanh quang
hieu quan » hieu qua, lieu quan, thien quan
vua trong » qua trong, va trong, nua trong
dua trong » qua trong, da trong, dia trong
cong doan » cong dan, cong hoan, dong doanh
doan van » doan va, hoang van, luan van

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

• Performing a fuzzy search may retrieve terms with similar spellings: nghe hieu quan - nhanh mang ((vua trong) or (dua trong)) cong doan van ban~.
• If you are trying to use Boolean operators, they must be ALL CAPS: nghe hieu quan - nhanh mang ((vua trong) OR (dua trong)) cong doan van ban*.