Perhaps you should try some spelling variations:
thien hach » thien thanh, hien hanh
nhung cong » thong cong, hang cong, nhung don
hoc thien » hoc hien, hoc thieu, hoc thiet
trinh cua » tinh cua, trinh quan, trinh luan
dung cong » dung trong
tac toan » tap toan, tam toan, hach toan
toan tap » toan ban

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