Perhaps you should try some spelling variations:
chieu sach » chinh sach, chiet tach, chieu sang
dung cong » dung trong
cong hach » cong sach, cong thanh, cong khanh
anh hang » anh hoang, anh hung, anh bang
hach van » bach van, cach van, hanh van
hieu va » lieu va, hieu qua
hang su » dang su, nang su, bang su

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 va) or (chieu sach)) - anh hang su dung cong hach van ban~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((hieu va) OR (chieu sach)) - anh hang su dung cong hach van ban*.