Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
vu sach » vu bach, vu khach
va hanh » va thanh, va danh, ban hanh
cau luc » cau truc, cau phuc
hieu va » lieu va, hieu qua
lang xa » lang ha, dang xay, lang van
ly lang » ly hang, ly vang, le lang
su sach » so sach
cua tre » cua te, cuu tre, cua triet
va cau » van cau, va cac, va dau
vi cua » vai cua, di cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((vu sach) OR (su sach)) ly lang xa hoi. hieu va cau luc ((va hanh) or (van hanh)) vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((vu sach) OR (su sach)) ly lang xa hoi. hieu va cau luc ((va hanh) OR (van hanh)) vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((vu sach) OR (su sach)) ly lang xa hoi. hieu va cau luc ((va hanh) or (van hanh)) vi cua tre".
• Adding a wildcard symbol may retrieve word variants: ((vu sach) OR (su sach)) ly lang xa hoi. hieu va cau luc ((va hanh) or (van hanh)) vi cua tre*.