Perhaps you should try some spelling variations:
nhung cong » dung cong, thong cong, nhung don
hiem ngan » kim ngan, viem gan
hanh tinh » hanh trinh, nhanh tinh, thanh tinh
hang cong » dang cong, hang nong, bang cong
hoc hiem » hoc hien, hoc thieu, hoc thiet
tinh cua » trinh cua, sinh cua, tinh chat
san toan » van toan, dan toan, 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 hiem ngan - hanh tinh cua ((nhung cong) or (hang cong)) san toan cao~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc hiem ngan - hanh tinh cua ((nhung cong) OR (hang cong)) san toan cao.
• Adding a wildcard symbol may retrieve word variants: hoc hiem ngan - hanh tinh cua ((nhung cong) or (hang cong)) san toan cao*.