Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
dan viet » danh viet, dang viet, san viet
viet cua » viec cua, viet ca, viet qua
xang ma » tang ma, nang ma, rang ma
sang ma » tang ma, nang ma, sang tao
hieu ve » hieu va, hieu van
cac duc » cac du, cao duc, cac dac
cua tre » cua te, cuu tre, cua triet
ve cac » va cac, vien cac
va dan » ca dan, va dao, va dau

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

• Performing a fuzzy search may retrieve terms with similar spellings: toc sach y ((xang ma) or (sang ma)) hoi. hieu ve cac duc va dan viet cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach y ((xang ma) OR (sang ma)) hoi. hieu ve cac duc va dan viet cua tre*.