Perhaps you should try some spelling variations:
tu sach » thu sach, su sach, te sach
nang ma » tang ma, sang ma, nang cao
hieu va » lieu va, hieu qua
cac duc » cac du, cao duc, cac dac
va danh » va dan, va hanh, dia danh
va dinh » van dinh, va kinh, va tinh
ca cua » co cua
cua te » cua tu

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach y ((nang x) or (nang ma)) hoi. hieu va cac duc ((va danh) or (va dinh)) ca cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y ((nang x) OR (nang ma)) hoi. hieu va cac duc ((va danh) OR (va dinh)) ca cua te.
• Adding a wildcard symbol may retrieve word variants: tu sach y ((nang x) or (nang ma)) hoi. hieu va cac duc ((va danh) or (va dinh)) ca cua te*.