Perhaps you should try some spelling variations:
thien hach » thien thanh, hien hanh
thanh dung » thanh duong, thanh hung, hanh dung
thanh tung » thanh cong
hoc thien » hoc hien, hoc thieu, hoc thiet
van thanh » ban thanh, van tuan
dan than » dan chan, ban than, van than
va dung » van dung, va duong, vat dung

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc thien hach - ((thanh dung) OR (thanh tung)) va dung trong ((van thanh) or (dan than)) cao~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc thien hach - ((thanh dung) OR (thanh tung)) va dung trong ((van thanh) OR (dan than)) cao.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc thien hach - ((thanh dung) OR (thanh tung)) va dung trong ((van thanh) or (dan than)) cao".
• Adding a wildcard symbol may retrieve word variants: hoc thien hach - ((thanh dung) OR (thanh tung)) va dung trong ((van thanh) or (dan than)) cao*.