Perhaps you should try some spelling variations:
thuc day » thuc dan, thuc vat
so sach » so sanh, bo sach, co sach
day dan » day danh, dao dan, cay dan
van hai » van ha, van chat, van hanh
sach ty » sach y, sach tu, sach thu
van cac » van hac, van cau, van bac
lang xa » lang ha, dang xay, lang van
nang xa » nang x, nang ma, mang xa
cua tre » cua te, cuu tre, cua triet
dan va » doan va, dan ca, ban va
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: so sach ty ((nang xa) OR (lang xa)) hoi. hieu ((van cac) or (van hai)) thuc day dan va cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach ty ((nang xa) OR (lang xa)) hoi. hieu ((van cac) OR (van hai)) thuc day dan va cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach ty ((nang xa) OR (lang xa)) hoi. hieu ((van cac) or (van hai)) thuc day dan va cua tre*".