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
va hanh » van hanh, va thanh, va danh
va xanh » va danh, va anh, va banh
sach ky » sach y, sach ty, sach kem
nang xa » nang x, lang xa, nang ma
cua tre » cua te, cuu tre, cua triet
sac ky » cac ky, sai ky
di cua » dai cua, doi cua, de cua

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 xanh) or (va hanh)) di 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 xanh) OR (va hanh)) di cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su ((sach ky) OR (sac ky)) nang xa hoi. hieu vien sach nuoc ((va xanh) or (va hanh)) di cua tre".
• Adding a wildcard symbol may retrieve word variants: su ((sach ky) OR (sac ky)) nang xa hoi. hieu vien sach nuoc ((va xanh) or (va hanh)) di cua tre*.