Perhaps you should try some spelling variations:
sach kem » hanh kem
cac nuoc » cap nuoc, hoc nuoc, dat nuoc
dieu cua » dieu tra
nang xa » nang x, lang xa, nang ma
qua cac » cua cac
va danh » va dinh, va dan, dia danh
va hanh » van hanh, va thanh, ban hanh
cua tre » cua te, cuu tre, cua triet
sac ky » cac ky, sai ky

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 kem) or (sac ky)) nang xa hoi. hieu qua cac nuoc ((va danh) OR (va hanh)) dieu cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach kem) OR (sac ky)) nang xa hoi. hieu qua cac nuoc ((va danh) OR (va hanh)) dieu cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sach kem) or (sac ky)) nang xa hoi. hieu qua cac nuoc ((va danh) OR (va hanh)) dieu cua tre".
• Adding a wildcard symbol may retrieve word variants: tu ((sach kem) or (sac ky)) nang xa hoi. hieu qua cac nuoc ((va danh) OR (va hanh)) dieu cua tre*.