Perhaps you should try some spelling variations:
va thanh » gia thanh, ban thanh, va tinh
cua tre » cua te, cuu tre, cua triet
va hanh » van hanh, va danh, ban hanh
hieu va » lieu va, hieu qua
cac loc » cac lop, cac toc, cac hoc
ky tang » ky nang, ky dang, kho tang
ky lang » ky nang, ky dang, tay lang
vi cua » vai cua, di cua
tu san » thu san, tu ban, tu can

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

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