Perhaps you should try some spelling variations:
vien thanh » viet thanh, tien thanh, dien thanh
hiem ngan » kim ngan, viem gan
manh hung » anh huong
dung cong » dung trong
cong tinh » cong trinh, cong vinh, long tinh
hung tac » huong tac, hung tan, ung tac
tac dung » sach dung, xay dung, tin dung
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 ((vien thanh) or (hiem ngan)) - manh hung tac dung cong tinh toan tap~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((vien thanh) OR (hiem ngan)) - manh hung tac dung cong tinh toan tap.
• Adding a wildcard symbol may retrieve word variants: hoc ((vien thanh) or (hiem ngan)) - manh hung tac dung cong tinh toan tap*.