Perhaps you should try some spelling variations:
nuoc san » nuoc luan, nguoi san, nuoc quan
hieu va » lieu va, hieu qua
xuc san » xuc ban, luc sang, thuc san
benh vi » benh va, benh ve, benh li
cua tre » cua te, cuu tre, cua triet
va cam » va cham, va cac, va cao
vi cua » vai cua, di cua
x hoi » xa hoi, o hoi, x ho

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 y) or (cac ky)) nang x hoi. hieu va cam ((xuc san) or (nuoc san)) benh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach y) OR (cac ky)) nang x hoi. hieu va cam ((xuc san) OR (nuoc san)) benh vi cua tre.
• Adding a wildcard symbol may retrieve word variants: tu ((sach y) or (cac ky)) nang x hoi. hieu va cam ((xuc san) or (nuoc san)) benh vi cua tre*.