Perhaps you should try some spelling variations:
cac nuoc » cap nuoc, hoc nuoc, dat nuoc
su sach » so sach, vu sach
hieu va » lieu va, hieu qua
va lang » va nang, hoa lang
lang vi » hang vi, lang va, sang vi
cua tre » cuu tre, cua triet, dua tren
v nang » va nang, vu nang, van nang
cua te » cua tu

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach ((v nang) or (van dong)) xa hoi. hieu va cac nuoc va lang vi ((cua tre) OR (cua te))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ((v nang) OR (van dong)) xa hoi. hieu va cac nuoc va lang vi ((cua tre) OR (cua te)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ((v nang) or (van dong)) xa hoi. hieu va cac nuoc va lang vi ((cua tre) OR (cua te))".
• Adding a wildcard symbol may retrieve word variants: su sach ((v nang) or (van dong)) xa hoi. hieu va cac nuoc va lang vi ((cua tre) OR (cua te))*.