Perhaps you should try some spelling variations:
thanh trung » thanh tung
thien hach » thien thanh, hien hanh
nhung cong » dung cong, thong cong, hang cong
hieu cach » chieu sach, hieu ca, biet cach
hieu cac » hieu luc, hieu va, hieu van
trung va » truong va, trang va, trung ha
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.

• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((thien hach) OR (((hieu cach) OR (hieu cac)))) - thanh trung va nhung cong tan toan cau~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((thien hach) or (((hieu cach) OR (hieu cac)))) - thanh trung va nhung cong tan toan cau~".
• Adding a wildcard symbol may retrieve word variants: hoc ((thien hach) or (((hieu cach) OR (hieu cac)))) - thanh trung va nhung cong tan toan cau*.