Perhaps you should try some spelling variations:
phuong tinh » phuong trinh, phuong binh, khuong tinh
chieu sach » chinh sach, chiet tach, chieu sang
manh trung » manh tung, thanh trung, manh hung
hieu lang » chieu sang, hieu quang, nhieu tang
trung cua » truong cua, trung tuan, trung cap
cua bang » chua bang, cua ban, cua dang
toan cao » toan tap
toan ban » van ban

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)) - manh trung cua bang phuong tinh ((toan cao) OR (toan ban))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: theo ((chieu sach) OR (hieu lang)) - manh trung cua bang phuong tinh ((toan cao) OR (toan ban)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "theo ((chieu sach) or (hieu lang)) - manh trung cua bang phuong tinh ((toan cao) OR (toan ban))".
• Adding a wildcard symbol may retrieve word variants: theo ((chieu sach) or (hieu lang)) - manh trung cua bang phuong tinh ((toan cao) OR (toan ban))*.