Perhaps you should try some spelling variations:
chieu sach » chinh sach, chiet tach, chieu sang
hanh trung » thanh trung, hanh trang, manh trung
nhung cong » dung cong, thong cong, hang cong
trung thi » truong thi, trong thi, trung tri
thi nhung » thi nang, thi hong, thi huong
roman cau » ran cau
cong san » cong tac
toan cau » 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: hoc ((chieu sach) or (trieu tinh)) - hanh trung thi nhung cong san ((roman cau) OR (toan cau))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((chieu sach) OR (trieu tinh)) - hanh trung thi nhung cong san ((roman cau) OR (toan cau)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((chieu sach) or (trieu tinh)) - hanh trung thi nhung cong san ((roman cau) OR (toan cau))".
• Adding a wildcard symbol may retrieve word variants: hoc ((chieu sach) or (trieu tinh)) - hanh trung thi nhung cong san ((roman cau) OR (toan cau))*.