Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
hoc hang » hoc hanh, hoc bang, hoc tang
hang hoa » hang khoa, thanh hoa, hang va
nhan dan » phan dau, gian dan, nhan tai
doi tac » dong tac
doi tai » hoi tai, dai tai, moi tai
mo hoc » mon hoc, co hoc
hoc xa » hoc ma
hoi ca » hoi cua, hoi cac, hoi cau

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 ((doi tac) or (doi tai)), nghien cuu mo hoc hang hoa hoc xa hoi ca nhan dan~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ((doi tac) OR (doi tai)), nghien cuu mo hoc hang hoa hoc xa hoi ca nhan dan.
• Adding a wildcard symbol may retrieve word variants: toc sach ((doi tac) or (doi tai)), nghien cuu mo hoc hang hoa hoc xa hoi ca nhan dan*.