Perhaps you should try some spelling variations:
thieu sach » thien hach, hieu cach, theo sach
chieu sach » chinh sach, chiet tach, chieu sang
hanh trang » thanh trung, canh tranh, hanh trinh
thong cong » trong cong, tong cong, thong thong
thanh toan » thanh hoa, thanh san, tinh toan
trang he » trong he, trang ha, tang he
dan toan » van toan, dan than, manh toan

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc ((thieu sach) OR (chieu sach)) - hanh trang he thong cong ((dan toan) or (thanh toan)) cao~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((thieu sach) OR (chieu sach)) - hanh trang he thong cong ((dan toan) OR (thanh toan)) cao*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((thieu sach) OR (chieu sach)) - hanh trang he thong cong ((dan toan) or (thanh toan)) cao*".