Perhaps you should try some spelling variations:
sach duoc » sach dao, sach dung, sinh duoc
sach nuoc » cac nuoc, bach tuoc, dich nuoc
hanh hai » thanh hai, nhanh hai, hang hai
hai cua » thai cua, dai cua, hoi cua
va hanh » van hanh, va thanh, va danh
sach ky » sac ky, sach y, sach kem
hieu va » lieu va, hieu qua
sach ty » sach y, sach tu, sach thu
cua tre » cua te, cuu tre, cua triet
x hoi » xa hoi, o hoi, x ho

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 ty)) nang x hoi. hieu va ((sach nuoc) or (sach duoc)) va hanh hai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach ky) OR (sach ty)) nang x hoi. hieu va ((sach nuoc) OR (sach duoc)) va hanh hai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sach ky) OR (sach ty)) nang x hoi. hieu va ((sach nuoc) or (sach duoc)) va hanh hai cua tre".
• Adding a wildcard symbol may retrieve word variants: tu ((sach ky) OR (sach ty)) nang x hoi. hieu va ((sach nuoc) or (sach duoc)) va hanh hai cua tre*.