Perhaps you should try some spelling variations:
sach thu » sach thue, sach thieu, sach tham
dang xay » dang van, van xay
hieu cua » hieu qua, dieu cua, bieu cua
nam thuc » nam thuoc, am thuc, nam thu
su sach » so sach, vu sach
lang xa » lang ha, lang van
cua nam » cua tam, cua ngan, cua nhan
vat dao » va dao, van dao, vat da
cua tre » cua te, cuu tre, cua triet
dao va » dao van, tao va, do 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: su sach thu ((lang xa) or (dang xay)) hoi. hieu cua nam thuc vat dao va cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach thu ((lang xa) OR (dang xay)) hoi. hieu cua nam thuc vat dao va cua tre.
• Adding a wildcard symbol may retrieve word variants: su sach thu ((lang xa) or (dang xay)) hoi. hieu cua nam thuc vat dao va cua tre*.