Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
cua tre » cua te, cuu tre, cua triet
duc van » duc va, duc tan, duc manh
nang xa » nang x, lang xa, mang xa
nang ma » tang ma, sang ma, nang cao
sai ky » sac ky
ve cac » vien cac
vi cua » vai cua, di cua
tu sai » tu bai, tu san, tu cai

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

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