Perhaps you should try some spelling variations:
thieu hach » chieu sach, hieu cach, thieu cac
thien hach » thien thanh, hien hanh
dung cong » dung trong
cong tap » cuong tap, cong tac, cong tan
tap toan » tap doan, tap quan, bai toan
toan cao » toan ban, toan tap
nang su » dang su, nang du, nang suat
nang tu » nang du, nang luc

You may be able to get more results by adjusting your search query.

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