Perhaps you should try some spelling variations:
chieu sach » chinh sach, chiet tach, chieu sang
thong cong » trong cong, tong cong, thong thong
hieu lang » chieu sang, hieu quang, nhieu tang
hanh tang » hanh trang, anh tang, hanh mang
van thong » van thuong, van phong, va thong
trinh han » trinh quan
tang van » dang van, hoang van, trong van
han cau » hang cau, phan cau, van cau

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

• Performing a fuzzy search may retrieve terms with similar spellings: theo ((chieu sach) or (hieu lang)) - hanh tang van thong cong trinh han cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: theo ((chieu sach) OR (hieu lang)) - hanh tang van thong cong trinh han cau.
• Adding a wildcard symbol may retrieve word variants: theo ((chieu sach) or (hieu lang)) - hanh tang van thong cong trinh han cau*.