Perhaps you should try some spelling variations:
khong thong » thong thong, khong trong, thong thuong
luan khong » luan phong, luan phuong, luong khong
hieu quan » hieu qua, lieu quan, thien quan
hanh tang » hanh trang, anh tang, hanh mang
tang luan » dung luan
sang toan » sang than, quang toan, sang tao
dang toan » dang tran, dan toan, dung toan
hoc hieu » hoc thieu, hoc hien, doc hieu

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 quan - hanh tang luan khong thong ((sang toan) or (dang toan)) cao~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc hieu quan - hanh tang luan khong thong ((sang toan) OR (dang toan)) cao*.