Perhaps you should try some spelling variations:
chieu sach » chinh sach, chieu sang, chieu xanh
hanh tranh » canh tranh, hanh trinh, hanh trang
cua thuong » cua phuong, ca thuong, cua huong
cua truong » cua trung, xuan truong, cac truong
thong tap » thong cap, tong tap, thong tai
tap toan » tap doan, tap quan, bai toan
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 (chiet tach)) - hanh tranh ((cua thuong) OR (cua truong)) thong tap toan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((chieu sach) OR (chiet tach)) - hanh tranh ((cua thuong) OR (cua truong)) thong tap toan cau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((chieu sach) or (chiet tach)) - hanh tranh ((cua thuong) OR (cua truong)) thong tap toan cau".
• Adding a wildcard symbol may retrieve word variants: hoc ((chieu sach) or (chiet tach)) - hanh tranh ((cua thuong) OR (cua truong)) thong tap toan cau*.