Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
su triet » su viet, su tien, ve triet
thanh va » thanh van, hanh va, thanh ha
dang xay » dang van, van xay
cac dac » cac dan, cac dai, cac bac
cac duc » cac du, cao duc, cac nuoc
te sach » toc sach
sach ky » sac ky, sach y, sach ty
tang ha » lang ha, tang ma, trung ha

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

• Performing a fuzzy search may retrieve terms with similar spellings: te sach ky ((tang ha) or (dang xay)) hoi. hieu qua ((cac duc) or (cac dac)) ban thanh va su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ky ((tang ha) OR (dang xay)) hoi. hieu qua ((cac duc) OR (cac dac)) ban thanh va su triet.
• Adding a wildcard symbol may retrieve word variants: te sach ky ((tang ha) or (dang xay)) hoi. hieu qua ((cac duc) or (cac dac)) ban thanh va su triet*.