Perhaps you should try some spelling variations:
chieu sach » chinh sach, chiet tach, chieu xanh
chieu sang » chieu xanh, hieu lang, nhieu tang
thuc hung » thuc chung, thuc nhung, thuc cung
thuc dung » thuoc dung, thuy dung, tuc dung
cong toan » cong tan, cong hoan, cong tuan
toan phan » thanh phan, toan ban, hoa phan
tinh dan » trinh dan, tinh da, binh dan
phan dau » phan tu, hang dau

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc ((chieu sach) or (chieu sang)) - tinh dan ((thuc hung) OR (thuc dung)) cong toan phan dau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((chieu sach) OR (chieu sang)) - tinh dan ((thuc hung) OR (thuc dung)) cong toan phan dau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((chieu sach) or (chieu sang)) - tinh dan ((thuc hung) OR (thuc dung)) cong toan phan dau".
• Adding a wildcard symbol may retrieve word variants: hoc ((chieu sach) or (chieu sang)) - tinh dan ((thuc hung) OR (thuc dung)) cong toan phan dau*.