Perhaps you should try some spelling variations:
trung tuan » trung thanh, trung tam, tran tuan
nhung cong » dung cong, thong cong, hang cong
hien sach » dien sach, kien sach, thien hach
tang cua » mang cua, hang cua, tang luan
cong tac » cong ty
toan cau » toan cao, toan tap, toan tai
toan ban » van ban

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

• If you are trying to use Boolean operators, they must be ALL CAPS: hoc hien sach - hanh ((trung tuan) OR (tang cua)) nhung cong tac ((toan cau) OR (toan ban))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc hien sach - hanh ((trung tuan) or (tang cua)) nhung cong tac ((toan cau) OR (toan ban))~".
• Adding a wildcard symbol may retrieve word variants: hoc hien sach - hanh ((trung tuan) or (tang cua)) nhung cong tac ((toan cau) OR (toan ban))*.