Perhaps you should try some spelling variations:
va thanh » gia thanh, ban thanh, le thanh
so sach » so sanh, bo sach, co sach
sach ky » sac ky, sach y, sach ty
va tinh » may tinh
cao suc » cao su
hieu va » lieu va, hieu qua
cao duc » dao duc, giao duc, tao duoc
nang xa » nang x, lang xa, nang ma
cua tre » cua te, cuu tre, cua triet
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: so sach ky nang xa hoi. hieu va ((cao duc) or (cao suc)) ((va thanh) OR (va tinh)) vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach ky nang xa hoi. hieu va ((cao duc) OR (cao suc)) ((va thanh) OR (va tinh)) vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach ky nang xa hoi. hieu va ((cao duc) or (cao suc)) ((va thanh) OR (va tinh)) vi cua tre".
• Adding a wildcard symbol may retrieve word variants: so sach ky nang xa hoi. hieu va ((cao duc) or (cao suc)) ((va thanh) OR (va tinh)) vi cua tre*.