Perhaps you should try some spelling variations:
dang xay » dang van, van xay
qua than » qua thanh, qua phan, qua tan
ban hanh » ban hang
van hanh » van thanh, van anh, van ban
ky dang » ky nang, ky danh
xay hoi » xa hoi, tay hoi, cay phoi
than le » thanh le, tuan le, phan le
luu tre » luu tru, cuu tre, luy tre
te cac » ve cac, te cao, de cac
vi luu » vi lua

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((te cac) OR (tu cac)) ky dang xay hoi. hieu qua than le ((ban hanh) or (van hanh)) vi luu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((te cac) OR (tu cac)) ky dang xay hoi. hieu qua than le ((ban hanh) OR (van hanh)) vi luu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((te cac) OR (tu cac)) ky dang xay hoi. hieu qua than le ((ban hanh) or (van hanh)) vi luu tre".
• Adding a wildcard symbol may retrieve word variants: ((te cac) OR (tu cac)) ky dang xay hoi. hieu qua than le ((ban hanh) or (van hanh)) vi luu tre*.