Perhaps you should try some spelling variations:
qua than » qua thanh, qua phan, qua tan
ban hanh » ban hang
van hanh » van thanh, van anh, van ban
ky lang » ky nang, ky dang, tay lang
ky tang » ky nang, ky dang, kho tang
than le » thanh le, tuan le, phan le
luu tre » luu tru, cuu tre, luy tre
ve cac » va cac, vien 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: ve cac ((ky lang) or (ky tang)) xa 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: ve cac ((ky lang) OR (ky tang)) xa hoi. hieu qua than le ((ban hanh) OR (van hanh)) vi luu tre.
• Adding a wildcard symbol may retrieve word variants: ve cac ((ky lang) or (ky tang)) xa hoi. hieu qua than le ((ban hanh) or (van hanh)) vi luu tre*.