Perhaps you should try some spelling variations:
quoc sau » quoc su, quoc sach, quoc sang
quoc suu » quoc su, quoc sieu, duoc sua
te sach » toc sach
qua nay » qua ngay, qua xay, qua cay
benh vi » benh va, benh ve, benh li
cua tre » cua te, cuu tre, cua triet
y song » _ song, c song, hay song
k song » _ song, c song
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: te sach ((y song) or (k song)) xa hoi. hieu qua nay ((quoc sau) or (quoc suu)) benh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ((y song) OR (k song)) xa hoi. hieu qua nay ((quoc sau) OR (quoc suu)) benh vi cua tre.
• Adding a wildcard symbol may retrieve word variants: te sach ((y song) or (k song)) xa hoi. hieu qua nay ((quoc sau) or (quoc suu)) benh vi cua tre*.