Perhaps you should try some spelling variations:
cac trung » cac truong, dac trung, bac trung
cac truc » cau truc, cac tru, sach truc
nang xa » nang x, lang xa, nang ma
hieu ve » hieu va, hieu van
va hanh » van hanh, va thanh, va 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: tu ((cac ky) or (sach y)) nang xa hoi. hieu ve ((cac truc) OR (cac trung)) va hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((cac ky) OR (sach y)) nang xa hoi. hieu ve ((cac truc) OR (cac trung)) va hanh vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((cac ky) or (sach y)) nang xa hoi. hieu ve ((cac truc) OR (cac trung)) va hanh vi cua tre".
• Adding a wildcard symbol may retrieve word variants: tu ((cac ky) or (sach y)) nang xa hoi. hieu ve ((cac truc) OR (cac trung)) va hanh vi cua tre*.