Perhaps you should try some spelling variations:
chieu sach » chiet tach, chieu sang, chieu xanh
hanh trinh » canh tranh, hanh chinh
nhung cong » thong cong, hang cong, nhung don
dung cong » dung trong
trinh va » trinh van, trinh vat, trinh ve
san than » sang than, san thanh, ban than
than cau » toan cau, phan cau, than cap

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc ((chieu sach) or (chinh sach)) - hanh trinh va ((nhung cong) OR (dung cong)) san than cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((chieu sach) OR (chinh sach)) - hanh trinh va ((nhung cong) OR (dung cong)) san than cau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((chieu sach) or (chinh sach)) - hanh trinh va ((nhung cong) OR (dung cong)) san than cau".
• Adding a wildcard symbol may retrieve word variants: hoc ((chieu sach) or (chinh sach)) - hanh trinh va ((nhung cong) OR (dung cong)) san than cau*.