Perhaps you should try some spelling variations:
thanh trung » thanh tung
thieu qua » thieu cua, thieu quang, thien quan
cam nhung » cam hung, nam nhung, tham nhung
cong manh » cong danh, duong manh, cong thanh
manh toan » thanh toan, anh tuan, tinh toan
van hung » van dung, manh hung, van duong
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 ((hieu qua) OR (thieu qua)) - thanh trung ((cam nhung) OR (van hung)) cong manh toan cau~.
• Adding a wildcard symbol may retrieve word variants: hoc ((hieu qua) or (thieu qua)) - thanh trung ((cam nhung) or (van hung)) cong manh toan cau*.