Perhaps you should try some spelling variations:
manh trung » manh tung, thanh trung, manh hung
chieu sach » chinh sach, chiet tach, chieu sang
theo sach » thuoc sach, te sach, theo lich
cong sang » cong lang, cong vang, cong bang
trung va » truong va, trang va, trung ha
cong san » cong tac
tao cao » bao cao, toan cao

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

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