Perhaps you should try some spelling variations:
te sach » toc sach
hai cua » thai cua, dai cua, hoi cua
va danh » va dinh, va dan, dia danh
va hanh » van hanh, va thanh, ban hanh
cam duc » cam xuc, cao duc, pham duc
cua tre » cua te, cuu tre, cua triet
hieu va » lieu va, hieu qua
sang ma » tang ma, sang tao, mang may
nang ma » tang ma, nang cao, mang may
va cam » va cham, va cac, va cao

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