Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
vat danh » va danh, van danh, luat danh
cam thuc » am thuc, nam thuc, cam thu
danh va » doanh va, hanh va, anh va
ty hang » ly hang, thi hang, thu hang
cua tre » cua te, cuu tre, cua triet
ca hoi » cau hoi, cua hoi, xa hoi
va cam » va cham, va cac, va cao
va cua » va chua, via cua, ca cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((te sach) OR (toc sach)) ((ty hang) or (ty xang)) ca hoi. lieu va cam thuc vat danh va cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sach) OR (toc sach)) ((ty hang) OR (ty xang)) ca hoi. lieu va cam thuc vat danh va cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((te sach) OR (toc sach)) ((ty hang) or (ty xang)) ca hoi. lieu va cam thuc vat danh va cua tre".
• Adding a wildcard symbol may retrieve word variants: ((te sach) OR (toc sach)) ((ty hang) or (ty xang)) ca hoi. lieu va cam thuc vat danh va cua tre*.