Perhaps you should try some spelling variations:
hieu van » thien van, lieu va, hieu ve
hao quoc » han quoc, cao quoc, ha quoc
ban benh » san benh, ban banh, can benh
tu sach » thu sach, su sach, te sach
nang xa » nang x, lang xa, nang ma
hieu va » lieu va, hieu qua
ba benh » va benh, bo benh, bach benh
cua tre » cua te, cuu tre, cua triet
y nang » ky nang, ly nang, v nang
vi cua » vai cua, di cua

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 y nang xa hoi. ((hieu van) or (hieu va)) hao quoc ((ban benh) OR (ba benh)) vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y nang xa hoi. ((hieu van) OR (hieu va)) hao quoc ((ban benh) OR (ba benh)) vi cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach y nang xa hoi. ((hieu van) or (hieu va)) hao quoc ((ban benh) OR (ba benh)) vi cua tre*".