Perhaps you should try some spelling variations:
chieu sach » chiet tach, chieu sang, chieu xanh
hieu quan » hieu qua, lieu quan, thien quan
manh tung » manh hung, thanh tung
dung cong » dung trong
tung tam » trung tam, vung tam, dung tam
tam dung » tam duong, tac dung, tan dung
cong tap » cuong tap, cong tac, cong tan
tap doan » tap quan
doan cau » toan cau, doan dau, doan cap

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc ((hieu quan) or (((chieu sach) or (chinh sach)))) - manh tung tam dung cong tap doan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((hieu quan) OR (((chieu sach) OR (chinh sach)))) - manh tung tam dung cong tap doan cau.
• Adding a wildcard symbol may retrieve word variants: hoc ((hieu quan) or (((chieu sach) or (chinh sach)))) - manh tung tam dung cong tap doan cau*.