Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
hanh dao » lanh dao, thanh dat, thanh dam
sach ky » sac ky, sach y, sach ty
ky dang » ky nang, ky danh
dang ma » dang mau, dang mam, dang mat
hieu ve » hieu va, hieu van
truc va » thuc va, thuc vat, trung va
dao cua » dai cua, day cua, dan cua
cua tre » cua te, cuu tre, cua triet
ma hoi » mai hoi, xa hoi, ma hoa
ve cam » ve cham, ve cac, va cam

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 ky dang ma hoi. hieu ve cam ((duc va) or (truc va)) hanh dao cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ky dang ma hoi. hieu ve cam ((duc va) OR (truc va)) hanh dao cua tre.
• Adding a wildcard symbol may retrieve word variants: toc sach ky dang ma hoi. hieu ve cam ((duc va) or (truc va)) hanh dao cua tre*.