Perhaps you should try some spelling variations:
hieu quan » lieu quan, thien quan, lien quan
thu sach » tu sach, thuat sach, thuoc sach
sach doi » sach hoi, sach moi, sach dao
danh sai » dung sai, danh bat, danh dau
danh vai » danh va, doanh van, dang van
cau duc » cao duc, cau luc, chu duc
xay hoi » xa hoi, tay hoi, cay phoi
doi van » do van, doi va, doi ban
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: thu sach doi van xay hoi. ((hieu quan) or (hieu qua)) cau duc va ((danh vai) OR (danh sai)) cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach doi van xay hoi. ((hieu quan) OR (hieu qua)) cau duc va ((danh vai) OR (danh sai)) cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach doi van xay hoi. ((hieu quan) or (hieu qua)) cau duc va ((danh vai) OR (danh sai)) cua te".
• Adding a wildcard symbol may retrieve word variants: thu sach doi van xay hoi. ((hieu quan) or (hieu qua)) cau duc va ((danh vai) OR (danh sai)) cua te*.