Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
kho tang » cao tang
hanh cac » hang cac, hanh cat, nhanh cay
ban hanh » ban hang
ve chat » va chat, van chat
cac chu » cac thu, cac che, cac khu
duc ban » duc tan, duc van, dua ban
ve cham » va cham, vu cham, ve chim
tang ha » lang ha, tang ma, trung ha
chu tre » cho tre, chu tri, cuu tre

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)) kho tang ha noi. hieu ((ve cham) or (ve chat)) duc ban hanh cac chu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sach) OR (toc sach)) kho tang ha noi. hieu ((ve cham) OR (ve chat)) duc ban hanh cac chu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((te sach) OR (toc sach)) kho tang ha noi. hieu ((ve cham) or (ve chat)) duc ban hanh cac chu tre".
• Adding a wildcard symbol may retrieve word variants: ((te sach) OR (toc sach)) kho tang ha noi. hieu ((ve cham) or (ve chat)) duc ban hanh cac chu tre*.