Perhaps you should try some spelling variations:
thien hach » thien thanh, hien hanh
thanh tung » thanh cong
trung cong » truong cong, trong cong, trung uong
hoc thien » hoc hien, hoc thieu, hoc thiet
cua trung » cua truong, xuan trung, cua nhung
cong tan » cong tac, cong san, cong thanh
tan phan » toan phan, than phan, van phan

You may be able to get more results by adjusting your search query.

• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc thien hach - ((thanh trung) OR (thanh tung)) cua trung cong tan phan tu~".
• Adding a wildcard symbol may retrieve word variants: hoc thien hach - ((thanh trung) OR (thanh tung)) cua trung cong tan phan tu*.