Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
su sach » so sach, vu sach
sach de » cach de, sach dao, sach dat
de lang » den lang, de dang, de tang
lang xa » lang ha, dang xay, lang van
hieu va » lieu va, hieu qua
gia duc » giao duc, gia muc, gia thuc
va hanh » va thanh, va danh, ban hanh
va gia » va giai
vai va » mai va, dai va, hai va

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach de lang xa hoi. hieu va gia duc ((va hanh) or (van hanh)) vai va (thiet or thieu)~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach de lang xa hoi. hieu va gia duc ((va hanh) OR (van hanh)) vai va (thiet OR thieu).
• Adding a wildcard symbol may retrieve word variants: su sach de lang xa hoi. hieu va gia duc ((va hanh) or (van hanh)) vai va (thiet or thieu)*.