Perhaps you should try some spelling variations:
chieu sach » chinh sach, chiet tach, chieu sang
dung huong » dung thuong, dung phuong, dong huong
hieu manh » chieu xanh, hieu nganh, dieu hanh
trinh vat » trinh van, trinh luat, sinh vat
trinh va » trinh van, trinh ve, trinh vi
dan toan » van toan, dan than, manh 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: theo ((hieu manh) or (chieu sach)) - hanh ((trinh va) OR (trinh vat)) dung huong dan toan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: theo ((hieu manh) OR (chieu sach)) - hanh ((trinh va) OR (trinh vat)) dung huong dan toan cau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "theo ((hieu manh) or (chieu sach)) - hanh ((trinh va) OR (trinh vat)) dung huong dan toan cau".
• Adding a wildcard symbol may retrieve word variants: theo ((hieu manh) or (chieu sach)) - hanh ((trinh va) OR (trinh vat)) dung huong dan toan cau*.