Perhaps you should try some spelling variations:
chieu sach » chinh sach, chiet tach, chieu sang
hieu lang » chieu sang, hieu quang, nhieu tang
hanh tang » hanh trang, anh tang, hanh mang
cong tinh » cong trinh, cong vinh, long tinh
cua bang » chua bang, cua ban, cua hang
cua dang » cua cong, cua ban
toan cau » toan cao, toan ban, toan tap

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: theo ((chieu sach) OR (hieu lang)) - hanh tang ((cua bang) OR (cua dang)) cong tinh toan cau~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "theo ((chieu sach) or (hieu lang)) - hanh tang ((cua bang) OR (cua dang)) cong tinh toan cau~".
• Adding a wildcard symbol may retrieve word variants: theo ((chieu sach) or (hieu lang)) - hanh tang ((cua bang) OR (cua dang)) cong tinh toan cau*.