Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
tang hoa » hang hoa, tang ha, tang ho
duc minh » duc anh
hanh ve » hanh vi, hanh va, hanh kem
xuc ban » duc ban, cuc ban, quoc ban
ve cham » va cham, ve chat, vu cham
cua tre » cua te, cuu tre, cua triet
hieu ve » hieu va, hieu van
y tang » ky tang, 6 tang, 7 tang
ve cua » le cua, de cua, te cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((te sach) OR (toc sach)) y tang hoa hoc. hieu ve cham ((xuc ban) or (duc minh)) hanh ve cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sach) OR (toc sach)) y tang hoa hoc. hieu ve cham ((xuc ban) OR (duc minh)) hanh ve cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((te sach) OR (toc sach)) y tang hoa hoc. hieu ve cham ((xuc ban) or (duc minh)) hanh ve cua tre".
• Adding a wildcard symbol may retrieve word variants: ((te sach) OR (toc sach)) y tang hoa hoc. hieu ve cham ((xuc ban) or (duc minh)) hanh ve cua tre*.