Perhaps you should try some spelling variations:
danh vai » danh sai, danh va, doanh van
su sach » so sach, vu sach
vai cua » dai cua, hai cua, lai cua
va danh » va dinh, va dan, va hanh
cao luc » bao luc, cao duc, cao suc
cua tre » cua te, cuu tre, cua triet
hieu va » lieu va
lang xa » lang ha, dang xay, lang van
ky lang » ky nang, ky dang, ky tang
so sanh » do sanh
luc va » duc va, tuc va, loc 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) or (so sanh)) ky lang xa hoi. ((hieu va) OR (hieu qua)) cao luc va danh vai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sach) OR (so sanh)) ky lang xa hoi. ((hieu va) OR (hieu qua)) cao luc va danh vai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((su sach) or (so sanh)) ky lang xa hoi. ((hieu va) OR (hieu qua)) cao luc va danh vai cua tre".
• Adding a wildcard symbol may retrieve word variants: ((su sach) or (so sanh)) ky lang xa hoi. ((hieu va) OR (hieu qua)) cao luc va danh vai cua tre*.