Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
hanh tai » thanh tai, hang tai, han tai
nang doc » nang luc
hieu ve » hieu va, hieu van
tai cua » thai cua, tai cuc, tri cua
va hanh » van hanh, va thanh, va danh
cham va » chat va, pham va, chai va
cua tre » cua te, cuu tre, cua triet
hieu vu » hieu va, hieu su, dieu vu
nang co » nang cao, nang noi, nang hoc
va va » va van, va vua, va vai

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 y ((nang co) OR (nang doc)) hoi. ((hieu vu) or (hieu ve)) cham va va hanh tai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thuoc sach y ((nang co) OR (nang doc)) hoi. ((hieu vu) OR (hieu ve)) cham va va hanh tai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thuoc sach y ((nang co) OR (nang doc)) hoi. ((hieu vu) or (hieu ve)) cham va va hanh tai cua tre".
• Adding a wildcard symbol may retrieve word variants: thuoc sach y ((nang co) OR (nang doc)) hoi. ((hieu vu) or (hieu ve)) cham va va hanh tai cua tre*.