Perhaps you should try some spelling variations:
thanh vai » thanh hai, thanh van, thanh tai
cua triet » su triet, va triet
ban thanh » ban hanh, ban hang
cua viet » ca viet, hoa viet, cua vat
cam cua » ca cua, nam cua, cau cua
vu sach » vu bach, su sach, vu khach
hieu ve » hieu va, hieu van
van hoc » van hoa
ve cam » ve cham, ve cac, va cam
y tang » ky tang, 6 tang, 5 tang
7 tang » 6 tang

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

• Performing a fuzzy search may retrieve terms with similar spellings: vu sach ((y tang) or (7 tang)) van hoc. hieu ve cam cua ban thanh vai ((cua triet) OR (cua viet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu sach ((y tang) OR (7 tang)) van hoc. hieu ve cam cua ban thanh vai ((cua triet) OR (cua viet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "vu sach ((y tang) or (7 tang)) van hoc. hieu ve cam cua ban thanh vai ((cua triet) OR (cua viet))".
• Adding a wildcard symbol may retrieve word variants: vu sach ((y tang) or (7 tang)) van hoc. hieu ve cam cua ban thanh vai ((cua triet) OR (cua viet))*.