Perhaps you should try some spelling variations:
thieu xanh » chieu xanh, hieu manh, thien anh
trung chan » trung phan, trung can, trung nhan
trong chan » trong chuan, trong cham, trong can
cong thuat » trong thuat, vuong thuat, cong suat
hoc thieu » toc thieu, hoc hien
cong thuc » cong tac
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 thieu xanh - thanh ((trung chan) or (trong chan)) dung ((cong thuat) OR (cong thuc)) toan cao~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc thieu xanh - thanh ((trung chan) OR (trong chan)) dung ((cong thuat) OR (cong thuc)) toan cao.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc thieu xanh - thanh ((trung chan) or (trong chan)) dung ((cong thuat) OR (cong thuc)) toan cao".
• Adding a wildcard symbol may retrieve word variants: hoc thieu xanh - thanh ((trung chan) or (trong chan)) dung ((cong thuat) OR (cong thuc)) toan cao*.