Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
duc van » duc va, duc tan, duc manh
sach ky » sac ky, sach ty, sach kem
cua tre » cua te, cuu tre, cua triet
nang xa » nang x, lang xa, nang ma
va cao » va cac, va co, va dao
vi cua » vai cua, di cua
ve cam » ve cham, ve cac, va cam

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

• Performing a fuzzy search may retrieve terms with similar spellings: su ((sach ky) or (sach y)) nang xa hoi. hieu ((ve cam) or (va cao)) duc van hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su ((sach ky) OR (sach y)) nang xa hoi. hieu ((ve cam) OR (va cao)) duc van hanh vi cua tre.
• Adding a wildcard symbol may retrieve word variants: su ((sach ky) or (sach y)) nang xa hoi. hieu ((ve cam) or (va cao)) duc van hanh vi cua tre*.