Perhaps you should try some spelling variations:
chiet tach » chieu sach
nhung cong » dung cong, thong cong, hang cong
hieu lang » chieu sang, hieu quang, nhieu tang
hanh hang » thanh hang, hang hang, hanh han
cong dan » cong san, cong tan, huong dan
toan cau » toan ban, toan tap, toan tai
toan cao » toan ban, toan tap

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

• Performing a fuzzy search may retrieve terms with similar spellings: theo ((hieu lang) or (chiet tach)) - hanh hang va nhung cong dan ((toan cau) OR (toan cao))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: theo ((hieu lang) OR (chiet tach)) - hanh hang va nhung cong dan ((toan cau) OR (toan cao)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "theo ((hieu lang) or (chiet tach)) - hanh hang va nhung cong dan ((toan cau) OR (toan cao))".
• Adding a wildcard symbol may retrieve word variants: theo ((hieu lang) or (chiet tach)) - hanh hang va nhung cong dan ((toan cau) OR (toan cao))*.