Perhaps you should try some spelling variations:
cong thuoc » cong thuc, long thuoc, cong thuong
dong thuoc » dung thuoc, dang thuoc, don thuoc
hoc thiet » hoc thieu, hoc thuyet, hoc hien
dung cong » dung trong
ho chiet » ho chieu, ho thiet, hoa thiet
cong tan » cong tac, cong san, cong thanh
tan toan » tan tran, tap toan, van toan
toan cau » 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: ((ho chiet) or (hoc thiet)) tach - thanh ((cong thuoc) OR (dong thuoc)) dung cong tan toan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((ho chiet) OR (hoc thiet)) tach - thanh ((cong thuoc) OR (dong thuoc)) dung cong tan toan cau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((ho chiet) or (hoc thiet)) tach - thanh ((cong thuoc) OR (dong thuoc)) dung cong tan toan cau".
• Adding a wildcard symbol may retrieve word variants: ((ho chiet) or (hoc thiet)) tach - thanh ((cong thuoc) OR (dong thuoc)) dung cong tan toan cau*.