Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
sach thu » sach thue, sach thieu, sach tham
thuc day » thuc dan, thuc vat
qua cham » qua hai, qua cac, va cham
nang mai » nang ma, nang tai, lang mai
thu nang » thi nang, thu hang, thu bang
qua cam » qua cac, qua ca, qua cai
mai hoi » mai khoi, dai hoi, lai hoi
danh di » danh du, xanh di, danh dien
hanh de » hanh ve, hanh kem
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: toc sach thu nang mai hoi. hieu ((qua cam) OR (qua cham)) thuc day ((danh di) or (hanh de)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach thu nang mai hoi. hieu ((qua cam) OR (qua cham)) thuc day ((danh di) OR (hanh de)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach thu nang mai hoi. hieu ((qua cam) OR (qua cham)) thuc day ((danh di) or (hanh de)) cua tre".
• Adding a wildcard symbol may retrieve word variants: toc sach thu nang mai hoi. hieu ((qua cam) OR (qua cham)) thuc day ((danh di) or (hanh de)) cua tre*.