Perhaps you should try some spelling variations:
vien sach » vien bach, dien sach, viet sach
hieu vien » hieu hien, hieu viec, thieu nien
sach nuoc » sach duoc, cac nuoc, bach tuoc
doi cua » dai cua, hoi cua
va hanh » van hanh, va thanh, va danh
sach ky » sach y, sach ty, sach kem
nang xa » nang x, lang xa, nang ma
cua tre » cua te, cuu tre, cua triet
va anh » van anh, va danh, va banh
sac ky » cac ky, sai ky

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

• Performing a fuzzy search may retrieve terms with similar spellings: su ((sach ky) or (sac ky)) nang xa hoi. hieu vien sach nuoc ((va anh) or (va hanh)) doi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su ((sach ky) OR (sac ky)) nang xa hoi. hieu vien sach nuoc ((va anh) OR (va hanh)) doi cua tre.
• Adding a wildcard symbol may retrieve word variants: su ((sach ky) or (sac ky)) nang xa hoi. hieu vien sach nuoc ((va anh) or (va hanh)) doi cua tre*.