Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
hanh tai » thanh tai, hang tai, han tai
sach ty » sach y, sach tu, sach thu
tai cua » thai cua, tai cuc, tri cua
cua tre » cua te, cuu tre, cua triet
nang ma » tang ma, sang ma, nang cao
hieu su » hieu sau, tieu su, hieu so
ty nang » ky nang, ty xang, ty hang
soc va » loc va, doc va, goc va
ma hoi » mai hoi, xa hoi, ma hoa

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

• Performing a fuzzy search may retrieve terms with similar spellings: thuoc sach ty nang ma hoi. ((hieu su) or (hieu qua)) cham ((soc va) OR (hoc va)) hanh tai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thuoc sach ty nang ma hoi. ((hieu su) OR (hieu qua)) cham ((soc va) OR (hoc va)) hanh tai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thuoc sach ty nang ma hoi. ((hieu su) or (hieu qua)) cham ((soc va) OR (hoc va)) hanh tai cua tre".
• Adding a wildcard symbol may retrieve word variants: thuoc sach ty nang ma hoi. ((hieu su) or (hieu qua)) cham ((soc va) OR (hoc va)) hanh tai cua tre*.