Perhaps you should try some spelling variations:
thien hach » thien thanh, hien hanh
trung cua » truong cua, trung tuan, trung cap
dang cong » dung cong
hieu cac » hieu luc, hieu va, hieu van
tung cua » tuong cua, dung cua, tang cua
cong tac » cong ty
tac toan » tap toan, tam toan, hach 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: hoc ((thien hach) or (hieu cac)) - thanh ((tung cua) OR (trung cua)) dang cong tac toan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((thien hach) OR (hieu cac)) - thanh ((tung cua) OR (trung cua)) dang cong tac toan cau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((thien hach) or (hieu cac)) - thanh ((tung cua) OR (trung cua)) dang cong tac toan cau".
• Adding a wildcard symbol may retrieve word variants: hoc ((thien hach) or (hieu cac)) - thanh ((tung cua) OR (trung cua)) dang cong tac toan cau*.