Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
nang noi » nang doc
hieu cua » hieu qua, dieu cua, bieu cua
tu sach » thu sach, su sach, te sach
tuc van » thuc van, truc van, tuc va
hanh di » hanh vi, hanh de, hang di
nang ra » lang ra, nang ro, nang va
nang ma » tang ma, sang ma, nang cao
sach ky » sac ky, sach y, sach ty
cac tuc » cac toc, cac tu, cac tac
di cua » dai cua, doi cua, de 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 ky ((nang noi) or (((nang ra) or (nang ma)))) hoi. hieu cua cac tuc van hanh di cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky ((nang noi) OR (((nang ra) OR (nang ma)))) hoi. hieu cua cac tuc van hanh di cua te.
• Adding a wildcard symbol may retrieve word variants: tu sach ky ((nang noi) or (((nang ra) or (nang ma)))) hoi. hieu cua cac tuc van hanh di cua te*.