Perhaps you should try some spelling variations:
sach thu » sach thue, sach thieu, sach tham
thuc va » thuc vat, thuc dan, thuc day
van hai » van ha, van chat, van hanh
van cac » van hac, van cau, van bac
sach ty » sach y, sach tu, xach tay
nang xa » nang x, lang xa, nang ma
cua tre » cua te, cuu tre, cua triet
va dan » ca dan, va dao, va dau
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.

• If you are trying to use Boolean operators, they must be ALL CAPS: so ((sach ty) OR (sach thu)) nang xa hoi. hieu ((van cac) OR (van hai)) thuc va dan va cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so ((sach ty) OR (sach thu)) nang xa hoi. hieu ((van cac) or (van hai)) thuc va dan va cua tre~".
• Adding a wildcard symbol may retrieve word variants: so ((sach ty) OR (sach thu)) nang xa hoi. hieu ((van cac) or (van hai)) thuc va dan va cua tre*.