Perhaps you should try some spelling variations:
cac nuoc » cap nuoc, hoc nuoc, dat nuoc
su sach » so sach, vu sach
ly nang » ky nang, ly hang, ly vang
hieu va » lieu va, hieu qua
va hang » van hang, va nang, va lang
y nang » ky nang, v nang, may nang
vi cua » vai cua
di cua » dai cua, doi cua, de cua

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 ((y nang) or (ly nang)) xa hoi. hieu va cac nuoc va hang ((vi cua) OR (di cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ((y nang) OR (ly nang)) xa hoi. hieu va cac nuoc va hang ((vi cua) OR (di cua)) tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ((y nang) or (ly nang)) xa hoi. hieu va cac nuoc va hang ((vi cua) OR (di cua)) tre".
• Adding a wildcard symbol may retrieve word variants: su sach ((y nang) or (ly nang)) xa hoi. hieu va cac nuoc va hang ((vi cua) OR (di cua)) tre*.