Perhaps you should try some spelling variations:
trinh vi » trinh va, trinh ve, trinh viet
cua tre » cua te, cuu tre, cua triet
sach ty » sach y, sach tu, sach thu
lang xa » lang ha, dang xay, lang van
hieu va » lieu va, hieu qua
tinh vi » tinh voi, tinh va, dinh vi
luc va » duc va, tuc va, loc va
sac ky » cac ky, sai ky
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: su ((sac ky) or (sach ty)) lang xa hoi. hieu va coc luc va ((tinh vi) OR (trinh vi)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su ((sac ky) OR (sach ty)) lang xa hoi. hieu va coc luc va ((tinh vi) OR (trinh vi)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su ((sac ky) or (sach ty)) lang xa hoi. hieu va coc luc va ((tinh vi) OR (trinh vi)) cua tre".
• Adding a wildcard symbol may retrieve word variants: su ((sac ky) or (sach ty)) lang xa hoi. hieu va coc luc va ((tinh vi) OR (trinh vi)) cua tre*.