Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
hieu van » hieu va, thien van, lieu va
thanh do » thanh de, thanh pho, thanh hoa
vu sach » vu bach, su sach, vu khach
cac lop » cac hop, cac loai
xay hoi » xa hoi, tay hoi, cay phoi
ky danh » ky anh, ky dang
ty danh » ty doanh, ty anh, te danh
cac lo » cac co, cac bo, cac ho
do cua » doi cua, co cua, de cua
cua te » cua tu

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 ((ty danh) or (ky danh)) xay hoi. hieu van ((cac lo) OR (cac lop)) ban thanh do cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu sach ((ty danh) OR (ky danh)) xay hoi. hieu van ((cac lo) OR (cac lop)) ban thanh do cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "vu sach ((ty danh) or (ky danh)) xay hoi. hieu van ((cac lo) OR (cac lop)) ban thanh do cua te".
• Adding a wildcard symbol may retrieve word variants: vu sach ((ty danh) or (ky danh)) xay hoi. hieu van ((cac lo) OR (cac lop)) ban thanh do cua te*.