Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
su sach » so sach, vu sach
tru van » truc van, tu van, tru va
cac tru » ca tru, cac tro, cac thu
hieu ve » hieu va, hieu van
lang xa » lang ha, dang xay, lang van
cua tre » cua te, cuu tre, cua triet
sach v » sach va, sach y, sach 2
ve cac » va cac, vien cac
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: su sach v ((lang xa) or (((mang may) or (nang cao)))) hoi. hieu ve cac tru van hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach v ((lang xa) OR (((mang may) OR (nang cao)))) hoi. hieu ve cac tru van hanh vi cua tre.
• Adding a wildcard symbol may retrieve word variants: su sach v ((lang xa) or (((mang may) or (nang cao)))) hoi. hieu ve cac tru van hanh vi cua tre*.