Perhaps you should try some spelling variations:
hoang hai » hoang thi
hoang van » hang va
nam thuc » nam thuoc, nam thu, nam tu
cua viet » ca viet, hoa viet, cua vat
bo sach » co sach, hoc sach
nang xa » nang x, lang xa, nang ma
hieu he » hieu ve, hiem he, hieu le
y nang » ky nang, ly nang, v nang

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

• Performing a fuzzy search may retrieve terms with similar spellings: bo sach y nang xa hoi. hieu he ((nam thuc) or (am thuc)) dat ((hoang hai) OR (hoang van)) cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: bo sach y nang xa hoi. hieu he ((nam thuc) OR (am thuc)) dat ((hoang hai) OR (hoang van)) cua viet*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "bo sach y nang xa hoi. hieu he ((nam thuc) or (am thuc)) dat ((hoang hai) OR (hoang van)) cua viet*".