Perhaps you should try some spelling variations:
cac nuoc » cap nuoc, hoc nuoc, dat nuoc
so sach » so sanh, bo sach, co sach
nang xa » nang x, lang xa, nang ma
hieu va » lieu va, hieu qua
lang vi » hang vi, sang vi, lang viet
lang va » lang van, hang va, lang ha
cua tre » cua te, cuu tre, cua triet
sach v » sach va, sach y, sach 2
v nang » va nang, vu nang, van nang

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

• Performing a fuzzy search may retrieve terms with similar spellings: so sach v nang xa hoi. hieu va cac nuoc va ((lang vi) or (lang va)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach v nang xa hoi. hieu va cac nuoc va ((lang vi) OR (lang va)) cua tre.
• Adding a wildcard symbol may retrieve word variants: so sach v nang xa hoi. hieu va cac nuoc va ((lang vi) or (lang va)) cua tre*.