Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
sach tay » xach tay, sach hay, sach nay
tay tang » tay lang, tay trung, tay quang
hieu van » hieu va, thien van, lieu va
ban hanh » ban hang
cua viet » ca viet, hoa viet, cua dieu
tang xa » trang xa, tang ma, lang xa
van cac » van hac, van cau, van bac
cac duc » cac du, cao duc, cac dac
duc ban » duc tan, duc van, dua ban
hanh va » hang va, hanh vi

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

• Performing a fuzzy search may retrieve terms with similar spellings: toc sach tay tang xa hoi. hieu van cac duc ban hanh va ((cua viet) or (cua vat))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach tay tang xa hoi. hieu van cac duc ban hanh va ((cua viet) OR (cua vat)).
• Adding a wildcard symbol may retrieve word variants: toc sach tay tang xa hoi. hieu van cac duc ban hanh va ((cua viet) or (cua vat))*.