Perhaps you should try some spelling variations:
sach thu » sach thue, sach thieu, sach tham
nam thuc » nam thuoc, am thuc, nam thu
thuc van » thuc vat, thuc dan, thuc va
van dung » van dong, xay dung, tin dung
dung doi » huong doi, dung tai, dung co
nang xa » nang x, lang xa, nang ma
qua nam » quan nam, cua nam, quang nam
doi cua » dai cua, hoi cua
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: su ((sach thu) or (sach y)) nang xa hoi. hieu qua nam thuc van dung doi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su ((sach thu) OR (sach y)) nang xa hoi. hieu qua nam thuc van dung doi cua tre.
• Adding a wildcard symbol may retrieve word variants: su ((sach thu) or (sach y)) nang xa hoi. hieu qua nam thuc van dung doi cua tre*.