Perhaps you should try some spelling variations:
thien van » thi van
thu sach » tu sach, thuat sach, thuoc sach
toc sach » hoc sach, doc sach, thuoc sach
hanh tai » thanh tai, hang tai, han tai
nam thuc » nam thuoc, am thuc, nam thu
tai cua » thai cua, tai cuc, tri cua
va hanh » van hanh, va thanh, va danh
thuc va » thuc vat, thuc dan, thuc day
dang ha » dong ha, dung ha, lang ha
dang xa » dang xay, lang xa, dang va
cua tre » cua te, cuu tre, cua triet

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((thu sach) or (toc sach)) ky ((dang xa) OR (dang ha)) hoi. thien van nam thuc va hanh tai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((thu sach) OR (toc sach)) ky ((dang xa) OR (dang ha)) hoi. thien van nam thuc va hanh tai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((thu sach) or (toc sach)) ky ((dang xa) OR (dang ha)) hoi. thien van nam thuc va hanh tai cua tre".
• Adding a wildcard symbol may retrieve word variants: ((thu sach) or (toc sach)) ky ((dang xa) OR (dang ha)) hoi. thien van nam thuc va hanh tai cua tre*.