Perhaps you should try some spelling variations:
dang thanh » dong thanh, dang hanh, hoang thanh
thuat van » thuat san, thuat va, thuat ban
van hang » van khang, van hoang, van thang
hang kho » hang khoa, khang kho, hang cho
kho khan » khoa kham, khoa than
thanh ha » thanh hoa, thanh hai, nhanh ha
su dang » su dung
ha thi » pham thi

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( thuat van hang kho khan đong luc ) or ( su dang thanh ha thi đong luc ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( thuat van hang kho khan đong luc ) OR ( su dang thanh ha thi đong luc )).
• Adding a wildcard symbol may retrieve word variants: (( thuat van hang kho khan đong luc ) or ( su dang thanh ha thi đong luc ))*.