Perhaps you should try some spelling variations:
trinh luan » trinh quan, trinh han, trinh toan
hang cong » dang cong, bang cong, thanh cong
hang nong » thang long, han tong
theo chu » theo chieu, cho chu, chao chu
chu sach » cau sach, thu sach, chieu sach
san toan » van toan, dan toan, manh toan
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 chu sach - hanh ((trinh luan) OR (trinh luat)) ((hang cong) or (hang nong)) san toan cao~.
• If you are trying to use Boolean operators, they must be ALL CAPS: theo chu sach - hanh ((trinh luan) OR (trinh luat)) ((hang cong) OR (hang nong)) san toan cao.
• The words AND, OR and NOT may confuse the search; try adding quotes: "theo chu sach - hanh ((trinh luan) OR (trinh luat)) ((hang cong) or (hang nong)) san toan cao".
• Adding a wildcard symbol may retrieve word variants: theo chu sach - hanh ((trinh luan) OR (trinh luat)) ((hang cong) or (hang nong)) san toan cao*.