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