Perhaps you should try some spelling variations:
thuat sach » thuat lanh, thuat san
toc sach » hoc sach, doc sach, thuoc sach
kho tang » cao tang
hieu van » hieu va, thien van, lieu va
van hanh » van thanh, ban hanh, van anh
tang ma » mang may, tang van
van cac » van hac, van cau, van bac
cac duc » cac du, cao duc, cac dac
duc van » duc va, duc tan, duc manh
cua tre » cua te, cuu tre, cua triet
ma hoi » mai hoi, xa hoi, ma hoa
vi cua » vai cua, di cua

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) or (thuat sach)) kho tang ma hoi. hieu van cac duc van hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((toc sach) OR (thuat sach)) kho tang ma hoi. hieu van cac duc van hanh vi cua tre.
• Adding a wildcard symbol may retrieve word variants: ((toc sach) or (thuat sach)) kho tang ma hoi. hieu van cac duc van hanh vi cua tre*.