Perhaps you should try some spelling variations:
chieu sach » chinh sach, chiet tach, chieu sang
nhung cong » thong cong, hang cong, nhung don
hieu lang » chieu sang, hieu quang, nhieu tang
hanh manh » hanh mang, lanh manh, hoang manh
dung cong » dung trong
manh cua » doanh cua, ban cua
dan toan » van toan, dan than, manh toan
toan tap » toan ban

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: doc ((hieu lang) OR (chieu sach)) - hanh manh cua ((nhung cong) OR (dung cong)) dan toan tap~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc ((hieu lang) or (chieu sach)) - hanh manh cua ((nhung cong) OR (dung cong)) dan toan tap~".
• Adding a wildcard symbol may retrieve word variants: doc ((hieu lang) or (chieu sach)) - hanh manh cua ((nhung cong) OR (dung cong)) dan toan tap*.