Perhaps you should try some spelling variations:
nuoc luan » luc luan
hieu van » hieu va, thien van, lieu va
sach tu » sach thu, cach tu, sach ty
benh vi » benh va, benh ve, benh li
xuc san » xuc ban, luc sang, nuoc san
van dau » van dao, phan dau
nang xa » nang x, lang xa, nang ma
cua tre » cua te, cuu tre, cua triet
sac ky » cac ky, sai ky
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: tu ((sach tu) or (sac ky)) nang xa hoi. hieu van dau ((xuc san) or (nuoc luan)) benh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach tu) OR (sac ky)) nang xa hoi. hieu van dau ((xuc san) OR (nuoc luan)) benh vi cua tre.
• Adding a wildcard symbol may retrieve word variants: tu ((sach tu) or (sac ky)) nang xa hoi. hieu van dau ((xuc san) or (nuoc luan)) benh vi cua tre*.