Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
va thanh » gia thanh, ban thanh, va tinh
va hanh » van hanh, va danh, ban hanh
cam duc » cam xuc, cao duc, pham duc
hieu ve » hieu va, hieu van
cua tre » cua te, cuu tre, cua triet
nang ma » tang ma, sang ma, nang cao
ve cam » ve cham, ve cac, va cam
ma hoi » mai hoi, xa hoi, ma hoa
y nang » ky nang, ly nang, v nang

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((te sach) or (toc sach)) y nang ma hoi. hieu ve cam duc ((va hanh) OR (va thanh)) dai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sach) OR (toc sach)) y nang ma hoi. hieu ve cam duc ((va hanh) OR (va thanh)) dai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((te sach) or (toc sach)) y nang ma hoi. hieu ve cam duc ((va hanh) OR (va thanh)) dai cua tre".
• Adding a wildcard symbol may retrieve word variants: ((te sach) or (toc sach)) y nang ma hoi. hieu ve cam duc ((va hanh) OR (va thanh)) dai cua tre*.