Perhaps you should try some spelling variations:
co sach » bo sach, cuon sach, hoc sach
sach ky » sac ky, sach y, sach ty
cua tre » cua te, cua triet, dua tren
tinh va » tich va, trinh van, trinh vat
tinh vi » trinh vi, tinh voi, dinh vi
coc tuc » coc luc, hoc thuc, doc thuc
hieu va » lieu va, hieu qua
dang xa » dang xay, lang xa, dang ha
ky dang » ky nang, ky danh
cuu tre » cau tren, cau treo
tuc va » thuc va, truc va, tuc xa
va coc » va cuoc, va cac, va hoc

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 coc tuc va ((tinh vi) OR (tinh va)) ((cua tre) or (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: co sach ky dang xa hoi. hieu va coc tuc va ((tinh vi) OR (tinh va)) ((cua tre) OR (cuu tre)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "co sach ky dang xa hoi. hieu va coc tuc va ((tinh vi) OR (tinh va)) ((cua tre) or (cuu tre))".
• Adding a wildcard symbol may retrieve word variants: co sach ky dang xa hoi. hieu va coc tuc va ((tinh vi) OR (tinh va)) ((cua tre) or (cuu tre))*.