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