Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
kho tang » cao tang
va thanh » gia thanh, ban thanh, va tinh
cac nuoc » cap nuoc, hoc nuoc, dat nuoc
qua cac » cua cac
tu sach » thu sach, su sach, te sach
tang ma » mang may, tang van
ma hoi » mai hoi, xa hoi, ma hoa
cho ca » cho can, cho cay, cho cua

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

• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (toc sach)) kho tang ma hoi. hieu qua cac nuoc va thanh ((cho ca) OR (cho cac)) tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (toc sach)) kho tang ma hoi. hieu qua cac nuoc va thanh ((cho ca) OR (cho cac)) tre~".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (toc sach)) kho tang ma hoi. hieu qua cac nuoc va thanh ((cho ca) OR (cho cac)) tre*.