Perhaps you should try some spelling variations:
thanh nhat » thanh nhan, thanh nha, thanh hai
thien van » thi van
thuc dan » thuc hanh, hoc dan, thuc vat
sach va » sach xa, sach ha, sach dao
nang xa » nang x, lang xa, nang ma
van cam » van nam, van lam, van cau
thuc va » thuc vat, thuc day
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 va) or (sach y)) nang xa hoi. thien van cam ((thuc va) OR (thuc dan)) thanh nhat cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su ((sach va) OR (sach y)) nang xa hoi. thien van cam ((thuc va) OR (thuc dan)) thanh nhat cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su ((sach va) or (sach y)) nang xa hoi. thien van cam ((thuc va) OR (thuc dan)) thanh nhat cua tre".
• Adding a wildcard symbol may retrieve word variants: su ((sach va) or (sach y)) nang xa hoi. thien van cam ((thuc va) OR (thuc dan)) thanh nhat cua tre*.