Perhaps you should try some spelling variations:
thanh cau » thanh chau, thanh mau, nhanh cau
sach thi » sach thu, sach tai, sach thieu
nam thuc » nam thuoc, am thuc, nam thu
van hanh » van thanh, ban hanh, van ban
su triet » su viet, su tien, ve triet
tu sach » thu sach, su sach, te sach
qua nam » quan nam, cua nam, quang nam
van anh » van thanh, tuan anh, van minh
tai su » tai so, tai tu, lai su

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach thi thanh cau hoi. hieu qua nam thuc ((van hanh) OR (van anh)) tai su triet~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach thi thanh cau hoi. hieu qua nam thuc ((van hanh) OR (van anh)) tai su triet".
• Adding a wildcard symbol may retrieve word variants: tu sach thi thanh cau hoi. hieu qua nam thuc ((van hanh) OR (van anh)) tai su triet*.