Perhaps you should try some spelling variations:
nam thuc » nam thuoc, am thuc, nam thu
thuc day » thuc dan, thuc vat
day hanh » day nhanh, day thanh, dao hanh
su sach » so sach, vu sach
nang xa » nang x, nang ma, mang xa
lang xa » lang ha, dang xay, lang van
hieu ve » hieu va, hieu van
cua tre » cua te, cuu tre, cua triet
vi cua » vai cua, di 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 y ((nang xa) or (lang xa)) hoi. ((hieu ve) or (hieu qua)) nam thuc day hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach y ((nang xa) OR (lang xa)) hoi. ((hieu ve) OR (hieu qua)) nam thuc day hanh vi cua tre.
• Adding a wildcard symbol may retrieve word variants: su sach y ((nang xa) or (lang xa)) hoi. ((hieu ve) or (hieu qua)) nam thuc day hanh vi cua tre*.