Perhaps you should try some spelling variations:
sach day » sach dao, sach dat, sach dau
day nano » dan nano, day nang, day nhanh
ban hanh » ban hang
van hanh » van thanh, van anh, van ban
su sach » so sach, vu sach
cua tre » cua te, cuu tre, cua triet
ve cac » vien cac
va hoi » xa hoi, va hoc, va hoa
va cua » va chua, via cua, ca 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 day nano va hoi. hieu ((ve cac) OR (va cac)) duc ((van hanh) or (ban hanh)) va cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach day nano va hoi. hieu ((ve cac) OR (va cac)) duc ((van hanh) OR (ban hanh)) va cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach day nano va hoi. hieu ((ve cac) OR (va cac)) duc ((van hanh) or (ban hanh)) va cua tre".
• Adding a wildcard symbol may retrieve word variants: su sach day nano va hoi. hieu ((ve cac) OR (va cac)) duc ((van hanh) or (ban hanh)) va cua tre*.