Perhaps you should try some spelling variations:
sach thue » sach thieu, sach tham, cach thuc
thanh va » thanh van, hanh va, thanh ha
sach thu » sach thieu, sach tham, cach thuc
dau tren » dau tien, dat tren, dau tieng
xang ha » lang ha, tang ha, dang ha
cao luc » bao luc, cao duc, cao suc
luc gia » luoc gia, duc gia, quoc gia
hieu va » lieu va, hieu qua
ha hoi » hoa hoi, ha noi, xa hoi
va cao » va cac, va co, va dao

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc ((sach thu) OR (sach thue)) xang ha hoi. hieu va cao luc gia ((hanh vi) or (thanh va)) dau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((sach thu) OR (sach thue)) xang ha hoi. hieu va cao luc gia ((hanh vi) OR (thanh va)) dau tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((sach thu) OR (sach thue)) xang ha hoi. hieu va cao luc gia ((hanh vi) or (thanh va)) dau tren".
• Adding a wildcard symbol may retrieve word variants: hoc ((sach thu) OR (sach thue)) xang ha hoi. hieu va cao luc gia ((hanh vi) or (thanh va)) dau tren*.