Perhaps you should try some spelling variations:
theo chieu » theo tieu, theo chu, thi chieu
hanh tang » hanh trang, anh tang, hanh mang
ho chieu » hoc thieu, doi chieu, mot chieu
cong tap » cuong tap, cong tac, tong tap
cong tan » cong tac, cong san, cong thanh
toan cao » toan ban, toan tap
tang su » tang suc, trang su, dang su

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

• If you are trying to use Boolean operators, they must be ALL CAPS: ((theo chieu) OR (ho chieu)) sach - hanh tang su dung ((cong tap) OR (cong tan)) toan cao~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((theo chieu) or (ho chieu)) sach - hanh tang su dung ((cong tap) OR (cong tan)) toan cao~".
• Adding a wildcard symbol may retrieve word variants: ((theo chieu) or (ho chieu)) sach - hanh tang su dung ((cong tap) OR (cong tan)) toan cao*.