Perhaps you should try some spelling variations:
so sanh » do sanh
ky lang » ky nang, ky dang, tay lang
ky tang » ky nang, ky dang, kho tang
hieu va » lieu va, hieu qua
cac duc » cac du, cao duc, cac dac
va hanh » van hanh, va thanh, ban hanh
va danh » va dinh, va dan, dia danh
cua tre » cua te, cuu tre, cua triet
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: so sanh ((ky lang) OR (ky tang)) xa hoi. hieu va cac duc ((va hanh) or (va danh)) vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sanh ((ky lang) OR (ky tang)) xa hoi. hieu va cac duc ((va hanh) OR (va danh)) vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sanh ((ky lang) OR (ky tang)) xa hoi. hieu va cac duc ((va hanh) or (va danh)) vi cua tre".
• Adding a wildcard symbol may retrieve word variants: so sanh ((ky lang) OR (ky tang)) xa hoi. hieu va cac duc ((va hanh) or (va danh)) vi cua tre*.