Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
nhan tuc » nhan thuc, nhan luc, nhanh thuc
tu sach » thu sach, su sach, te sach
va hanh » va thanh, va danh, ban hanh
hoi cua » hoi chuc
hai cua » thai cua, dai cua, lai cua
va nhan » van nhan, ca nhan, va phan
hieu va » lieu va, hieu qua
sang ma » tang ma, nang ma, sang tao
y sang » _ sang, duy sang
ma hoi » mai hoi, xa hoi, ma hoa

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 sang ma hoi. hieu va nhan tuc ((va hanh) or (van hanh)) ((hai cua) or (hoi cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y sang ma hoi. hieu va nhan tuc ((va hanh) OR (van hanh)) ((hai cua) OR (hoi cua)) tre.
• Adding a wildcard symbol may retrieve word variants: tu sach y sang ma hoi. hieu va nhan tuc ((va hanh) or (van hanh)) ((hai cua) or (hoi cua)) tre*.