Perhaps you should try some spelling variations:
quan trong » gian trong
luan trong » luat trong, luan tuong, luong trong
hanh tang » hanh trang, anh tang, hanh mang
cuong tap » luong tap, cong tac, luong tai
theo cau » theo chu, theo cap, theo dau
cau sach » cao sach, hau sach, rau sach
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: theo cau sach - hanh tang ((luan trong) OR (quan trong)) cuong tap ((toan cau) OR (toan ban))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "theo cau sach - hanh tang ((luan trong) OR (quan trong)) cuong tap ((toan cau) or (toan ban))~".
• Adding a wildcard symbol may retrieve word variants: theo cau sach - hanh tang ((luan trong) OR (quan trong)) cuong tap ((toan cau) or (toan ban))*.