Perhaps you should try some spelling variations:
chieu sang » chieu xanh, hieu lang, nhieu tang
chieu sach » chinh sach, chiet tach, chieu xanh
hanh trong » hanh trang, anh trong, hinh trong
dung cong » dung trong
cong manh » cong danh, duong manh, cong thanh
cac dung » cach dung, cac duong, tac dung
toan cau » toan cao, toan ban, toan tai
toan tap » toan ban

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 sang) OR (chieu sach)) - hanh trong cac dung cong manh ((toan cau) or (toan tap))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((chieu sang) OR (chieu sach)) - hanh trong cac dung cong manh ((toan cau) OR (toan tap)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((chieu sang) OR (chieu sach)) - hanh trong cac dung cong manh ((toan cau) or (toan tap))".
• Adding a wildcard symbol may retrieve word variants: hoc ((chieu sang) OR (chieu sach)) - hanh trong cac dung cong manh ((toan cau) or (toan tap))*.