Perhaps you should try some spelling variations:
danh vai » danh sai, danh va, doanh van
co sach » bo sach, cuon sach, hoc sach
sach ky » sac ky, sach y, sach ty
vai cua » dai cua, hai cua, lai cua
dang xa » dang xay, lang xa, dang ha
hieu va » lieu va
ky dang » ky nang, ky danh
cua tre » cua te, cuu tre, cua triet
luc va » duc va, loc va
tuc va » thuc va, truc va, tuc xa

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

• Performing a fuzzy search may retrieve terms with similar spellings: co sach ky dang xa hoi. ((hieu va) OR (hieu qua)) cau ((luc va) or (tuc va)) danh vai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: co sach ky dang xa hoi. ((hieu va) OR (hieu qua)) cau ((luc va) OR (tuc va)) danh vai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "co sach ky dang xa hoi. ((hieu va) OR (hieu qua)) cau ((luc va) or (tuc va)) danh vai cua tre".
• Adding a wildcard symbol may retrieve word variants: co sach ky dang xa hoi. ((hieu va) OR (hieu qua)) cau ((luc va) or (tuc va)) danh vai cua tre*.