Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
nang ma » tang ma, sang ma, nang cao
hieu ve » hieu va, hieu van
cac xuc » cam xuc, cac nuoc, chat xuc
va danh » va dinh, va dan, va hanh
danh vi » hanh vi, dinh vi, danh di
luu tre » luu tru, cuu tre, luy tre
ve cac » va cac, vien cac
xuc va » duc va, tuc va, luc va
vi luu » vi lua

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: toc sach y ((nang x) OR (nang ma)) hoi. hieu ve cac xuc va danh vi luu tre~.
• Adding a wildcard symbol may retrieve word variants: toc sach y ((nang x) or (nang ma)) hoi. hieu ve cac xuc va danh vi luu tre*.