Perhaps you should try some spelling variations:
chieu sach » chinh sach, chiet tach, chieu sang
hien hanh » dieu hanh
hanh hang » thanh hang, hang hang, hanh han
lang cong » bang cong, hang cong, lang dong
dang cong » dung cong
hang cac » hang ca, hang cau, bang cac
dan than » dan chan, ban than, van than
than cau » toan cau, phan cau, than cap

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: toc ((chieu sach) OR (hien hanh)) - hanh hang cac ((lang cong) OR (dang cong)) dan than cau~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc ((chieu sach) or (hien hanh)) - hanh hang cac ((lang cong) OR (dang cong)) dan than cau~".
• Adding a wildcard symbol may retrieve word variants: toc ((chieu sach) or (hien hanh)) - hanh hang cac ((lang cong) OR (dang cong)) dan than cau*.