Perhaps you should try some spelling variations:
so sach » so sanh, co sach, hoc sach
bo sach » co sach, hoc sach
nang ma » tang ma, sang ma, nang cao
qua cao » qua cac, qua ca, qua cai
cao tuc » dao tuc, cao duc, cao suc
hanh va » hang va
v nang » va nang, vu nang, van nang
ma hoi » mai hoi, xa hoi, ma hoa
thiet » thieu

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((so sach) or (bo sach)) v nang ma hoi. hieu qua cao tuc xa ((hanh va) or (hanh vi)) va thiet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((so sach) OR (bo sach)) v nang ma hoi. hieu qua cao tuc xa ((hanh va) OR (hanh vi)) va thiet.
• Adding a wildcard symbol may retrieve word variants: ((so sach) or (bo sach)) v nang ma hoi. hieu qua cao tuc xa ((hanh va) or (hanh vi)) va thiet*.