Perhaps you should try some spelling variations:
phuong tinh » phuong trinh, phuong binh, khuong tinh
hung thang » cang thang, hung tran
theo chu » theo chieu, cho chu, chao chu
chu sach » cau sach, thu sach, chieu sach
cua bang » chua bang, cua ban, cua hang
cua dang » cua cong, cua ban
toan cau » toan cao, toan ban, toan tap

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

• Performing a fuzzy search may retrieve terms with similar spellings: theo chu sach - hung thang ((cua bang) or (cua dang)) phuong tinh toan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: theo chu sach - hung thang ((cua bang) OR (cua dang)) phuong tinh toan cau*.