Perhaps you should try some spelling variations:
thong cong » trong cong, tong cong, thong thong
hieu cach » hieu cac, chieu sach, hieu ca
dung cong » dung trong
toc hieu » toc thieu, doc hieu, hoc thieu
trung va » truong va, trung ha, trung tam
trang va » tran van, hang va
tan toan » tan tran, tap toan, van toan
toan cao » toan ban, toan tap

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 hieu cach - thanh ((trung va) OR (trang va)) ((dung cong) OR (thong cong)) tan toan cao~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc hieu cach - thanh ((trung va) OR (trang va)) ((dung cong) or (thong cong)) tan toan cao~".
• Adding a wildcard symbol may retrieve word variants: toc hieu cach - thanh ((trung va) OR (trang va)) ((dung cong) or (thong cong)) tan toan cao*.