Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
cac nuoc » cap nuoc, hoc nuoc, dat nuoc
dang xay » van xay
ban hanh » ban hang
dang van » hoang van, hang va
hieu ve » hieu va, hieu van
cac luc » cau luc, coc luc, cac cuoc
vi cua » vai cua, di 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: thuoc sach y ((dang xay) or (dang van)) hoi. hieu ve ((cac luc) OR (cac nuoc)) ban hanh vi cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thuoc sach y ((dang xay) OR (dang van)) hoi. hieu ve ((cac luc) OR (cac nuoc)) ban hanh vi cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thuoc sach y ((dang xay) or (dang van)) hoi. hieu ve ((cac luc) OR (cac nuoc)) ban hanh vi cua te".
• Adding a wildcard symbol may retrieve word variants: thuoc sach y ((dang xay) or (dang van)) hoi. hieu ve ((cac luc) OR (cac nuoc)) ban hanh vi cua te*.