Perhaps you should try some spelling variations:
thanh vai » thanh hai, thanh van, thanh tai
te sach » toc sach
sach tu » sach thu, cach tu, sach ty
vai cua » dai cua, hai cua, lai cua
thuc va » thuc vat, thuc dan, thuc day
cua tre » cua te, cuu tre, cua triet
nang xa » nang x, lang xa, nang ma
hieu va » lieu va
tu nang » tru nang, tu nong, tu nano
tuc va » truc va, tuc xa, duc va

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: te sach tu nang xa hoi. ((hieu va) OR (hieu qua)) co ((tuc va) or (thuc va)) thanh vai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach tu nang xa hoi. ((hieu va) OR (hieu qua)) co ((tuc va) OR (thuc va)) thanh vai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach tu nang xa hoi. ((hieu va) OR (hieu qua)) co ((tuc va) or (thuc va)) thanh vai cua tre".
• Adding a wildcard symbol may retrieve word variants: te sach tu nang xa hoi. ((hieu va) OR (hieu qua)) co ((tuc va) or (thuc va)) thanh vai cua tre*.