Perhaps you should try some spelling variations:
khien bang » phien ban, khien dong
hoc khien » hoc hien, hoc nghien, hoc thieu
dang cong » dung cong
cong hach » cong sach, cong thanh, cong khanh
hach toan » thanh toan, manh toan
trung va » truong va, trang va, trung tam
trung ha » trung hoc, trung tam, trung cap
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 khien bang - thanh ((trung va) or (trung ha)) dang cong hach toan cao~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc khien bang - thanh ((trung va) OR (trung ha)) dang cong hach toan cao.
• Adding a wildcard symbol may retrieve word variants: hoc khien bang - thanh ((trung va) or (trung ha)) dang cong hach toan cao*.