Perhaps you should try some spelling variations:
sach ky » sac ky, sach y, sach kem
sach ty » sach y, sach tu, sach thu
tang xa » trang xa, tang ma, lang xa
hieu va » lieu va, hieu qua
tinh vi » trinh vi, tinh voi, tinh va
cua tre » cua te, cuu tre, cua triet
va coc » va cuoc, va cac, va hoc
luc va » tuc va, loc va
vi cua » vai cua, di cua

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

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