Perhaps you should try some spelling variations:
thieu sach » chieu sach, hieu cach, theo sach
thien hach » thien thanh, hien hanh
hanh trinh » canh tranh, hanh chinh
trinh ve » trinh he, trinh va, trinh vi
ve thong » he thong, va thong, ve phong
cong dan » cong tan, huong dan, cong dong
cong san » cong tac
toan tap » toan ban

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 (thien hach)) - hanh trinh ve thong ((cong dan) or (cong san)) toan tap~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((thieu sach) OR (thien hach)) - hanh trinh ve thong ((cong dan) OR (cong san)) toan tap.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((thieu sach) OR (thien hach)) - hanh trinh ve thong ((cong dan) or (cong san)) toan tap".
• Adding a wildcard symbol may retrieve word variants: hoc ((thieu sach) OR (thien hach)) - hanh trinh ve thong ((cong dan) or (cong san)) toan tap*.