Perhaps you should try some spelling variations:
chieu sach » chinh sach, chiet tach, chieu sang
nhung cong » dung cong, hang cong, nhung don
thong cong » trong cong, tong cong, thong thong
hieu manh » chieu xanh, hieu nganh, dieu hanh
hanh tang » hanh trang, anh tang, hanh mang
tang cua » mang cua, hang cua, tang luan
tap toan » tap doan, tap quan, bai toan
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: theo ((hieu manh) or (chieu sach)) - hanh tang cua ((nhung cong) OR (thong cong)) tap toan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: theo ((hieu manh) OR (chieu sach)) - hanh tang cua ((nhung cong) OR (thong cong)) tap toan cau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "theo ((hieu manh) or (chieu sach)) - hanh tang cua ((nhung cong) OR (thong cong)) tap toan cau".
• Adding a wildcard symbol may retrieve word variants: theo ((hieu manh) or (chieu sach)) - hanh tang cua ((nhung cong) OR (thong cong)) tap toan cau*.