Perhaps you should try some spelling variations:
thien van » thi van
hieu van » hieu va, lieu va, hieu ve
van hanh » van thanh, ban hanh, van anh
tu sach » thu sach, su sach, te sach
nang xa » nang x, lang xa, nang ma
duc van » duc va, duc tan, duc manh
cua tre » cua te, cuu tre, cua triet
tu sac » tu cac, tu san, tu bac
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 sac) OR (tu sach)) ky nang xa hoi. ((hieu van) or (thien van)) pham duc van hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sac) OR (tu sach)) ky nang xa hoi. ((hieu van) OR (thien van)) pham duc van hanh vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sac) OR (tu sach)) ky nang xa hoi. ((hieu van) or (thien van)) pham duc van hanh vi cua tre".
• Adding a wildcard symbol may retrieve word variants: ((tu sac) OR (tu sach)) ky nang xa hoi. ((hieu van) or (thien van)) pham duc van hanh vi cua tre*.