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
song thanh » son thanh, dong thanh, rong thanh
cong thanh » dong thanh, cong trinh, cong tan
luat ban » luat bao, luat dan, luat bat
toan cau » toan cao, toan ban, toan tap

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