Perhaps you should try some spelling variations:
trinh luan » trinh luat, trinh quan, trinh toan
trinh han » trinh quan
bang cong » dang cong, bang song, hang cong
hang nong » thang long, han tong
theo cau » theo chu, theo cap, theo dau
cau sach » cao sach, hau sach, rau sach
san toan » van toan, dan toan, manh toan
toan ban » van ban

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

• Performing a fuzzy search may retrieve terms with similar spellings: theo cau sach - hanh ((trinh luan) OR (trinh han)) ((bang cong) or (hang nong)) san toan ban~.
• If you are trying to use Boolean operators, they must be ALL CAPS: theo cau sach - hanh ((trinh luan) OR (trinh han)) ((bang cong) OR (hang nong)) san toan ban.
• The words AND, OR and NOT may confuse the search; try adding quotes: "theo cau sach - hanh ((trinh luan) OR (trinh han)) ((bang cong) or (hang nong)) san toan ban".
• Adding a wildcard symbol may retrieve word variants: theo cau sach - hanh ((trinh luan) OR (trinh han)) ((bang cong) or (hang nong)) san toan ban*.