Perhaps you should try some spelling variations:
su sach » so sach, vu sach
hanh va » hang va, hanh vi
sach ky » sac ky, sach y, sach ty
cua tre » cua te, cuu tre, cua triet
sang ma » tang ma, nang ma, sang tao
ky sang » ky nang, ky dang, ky tang
ma hoi » mai hoi, xa hoi, ma hoa
va cua » va chua, via cua, ca cua
bo va » bao va, do va, co va
so va » so van, so vat, su va

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 sang ma hoi. hieu ((va bao) or (va bai)) ((bo va) OR (so va)) hanh va cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky sang ma hoi. hieu ((va bao) OR (va bai)) ((bo va) OR (so va)) hanh va cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky sang ma hoi. hieu ((va bao) or (va bai)) ((bo va) OR (so va)) hanh va cua tre".
• Adding a wildcard symbol may retrieve word variants: su sach ky sang ma hoi. hieu ((va bao) or (va bai)) ((bo va) OR (so va)) hanh va cua tre*.