Perhaps you should try some spelling variations:
hoc thieu » toc thieu, hoc hien
trong vat » trong van, trong va, trong hoat
trong dat » trong dam, trong dan, trong dao
dung cong » dung trong
cong san » cong tac
san toan » van toan, dan toan, manh toan
toan cao » toan ban, toan tap
doi chi » doi khi

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((doi chi) or (hoc thieu)) xanh - hanh ((trong vat) OR (trong dat)) dung cong san toan cao~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((doi chi) OR (hoc thieu)) xanh - hanh ((trong vat) OR (trong dat)) dung cong san toan cao.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((doi chi) or (hoc thieu)) xanh - hanh ((trong vat) OR (trong dat)) dung cong san toan cao".
• Adding a wildcard symbol may retrieve word variants: ((doi chi) or (hoc thieu)) xanh - hanh ((trong vat) OR (trong dat)) dung cong san toan cao*.