Perhaps you should try some spelling variations:
theo chieu » theo tieu, theo chu, thi chieu
hanh tang » hanh trang, anh tang, hanh mang
thong tap » thong cap, thong tai, thong lap
ho chieu » hoc thieu, doi chieu, mot chieu
tong tap » tuong tac, trong tan, cong tac
toan cau » toan cao, toan ban, toan tap
tang he » tang le, tang ha, bang he

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((ho chieu) or (theo chieu)) sach - hanh tang he thong ((thong tap) OR (tong tap)) toan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((ho chieu) OR (theo chieu)) sach - hanh tang he thong ((thong tap) OR (tong tap)) toan cau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((ho chieu) or (theo chieu)) sach - hanh tang he thong ((thong tap) OR (tong tap)) toan cau".
• Adding a wildcard symbol may retrieve word variants: ((ho chieu) or (theo chieu)) sach - hanh tang he thong ((thong tap) OR (tong tap)) toan cau*.