Perhaps you should try some spelling variations:
phuong dong » phuong dung, chuong duong, phuong dinh
theo chieu » theo tieu, ho chieu, theo chu
chieu sach » chinh sach, chiet tach, chieu sang
quang va » quang van, quan va, quang ma
tac toan » tap toan, tam toan, hach toan
toan cao » toan ban, toan tap

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

• The words AND, OR and NOT may confuse the search; try adding quotes: "theo chieu sach - tinh quang va ((phuong dong) OR (phuong hoang)) tac toan cao~".
• Adding a wildcard symbol may retrieve word variants: theo chieu sach - tinh quang va ((phuong dong) OR (phuong hoang)) tac toan cao*.