Perhaps you should try some spelling variations:
sach thu » sach thue, sach thieu, sach tham
dau truc » cau truc, dai truc, doan truc
hieu van » hieu va, thien van, lieu va
va hanh » van hanh, va thanh, va danh
truc va » thuc va, thuc vat, trung va
van dau » van dao, phan dau
cua tre » cua te, cuu tre, cua triet
sach ky » sac ky, sach y, sach ty
nang xa » lang xa, nang ma, 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: tu ((sach ky) or (sach thu)) ((nang xa) OR (nang x)) hoi. hieu van dau truc va hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach ky) OR (sach thu)) ((nang xa) OR (nang x)) hoi. hieu van dau truc va hanh vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sach ky) or (sach thu)) ((nang xa) OR (nang x)) hoi. hieu van dau truc va hanh vi cua tre".
• Adding a wildcard symbol may retrieve word variants: tu ((sach ky) or (sach thu)) ((nang xa) OR (nang x)) hoi. hieu van dau truc va hanh vi cua tre*.