Perhaps you should try some spelling variations:
thien hach » thien thanh, hien hanh
hoc thien » hoc hien, hoc thieu, hoc thiet
trinh cua » trinh luat, trinh quan, trinh luan
dung cong » dung trong
tinh cua » sinh cua, tinh chat, tranh cua
san toan » van toan, dan toan, manh toan
dan than » dan chan, ban than, van than

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 - hanh ((trinh cua) OR (tinh cua)) dung cong ((san toan) or (dan than)) tap~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc thien hach - hanh ((trinh cua) OR (tinh cua)) dung cong ((san toan) OR (dan than)) tap.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc thien hach - hanh ((trinh cua) OR (tinh cua)) dung cong ((san toan) or (dan than)) tap".
• Adding a wildcard symbol may retrieve word variants: hoc thien hach - hanh ((trinh cua) OR (tinh cua)) dung cong ((san toan) or (dan than)) tap*.