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

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