Perhaps you should try some spelling variations:
chieu sach » chinh sach, chieu sang, chieu xanh
hanh tran » hanh trang, thanh tran, hanh tram
van thong » van thuong, van phong, va thong
cong sach » ong sach, duong sach, luong sach
song sach » sang sach, ong sach, song bach
tran van » luan van
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 tran van thong ((cong sach) OR (song sach)) toan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((chieu sach) OR (chiet tach)) - hanh tran van thong ((cong sach) OR (song sach)) toan cau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((chieu sach) or (chiet tach)) - hanh tran van thong ((cong sach) OR (song sach)) toan cau".
• Adding a wildcard symbol may retrieve word variants: hoc ((chieu sach) or (chiet tach)) - hanh tran van thong ((cong sach) OR (song sach)) toan cau*.