Perhaps you should try some spelling variations:
su sach » so sach, vu sach
nang ho » nang hoc, nang co, tang ho
hieu va » lieu va, hieu qua
va dang » van dang, va nang, va lang
duc van » duc tan, duc manh, duc phan
cua tre » cua te, cuu tre, cua triet
nang o » nang co, nang ro, nang x
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 y ((nang o) OR (nang ho)) hoi. hieu va dang ((duc van) or (duc va)) hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach y ((nang o) OR (nang ho)) hoi. hieu va dang ((duc van) OR (duc va)) hanh vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach y ((nang o) OR (nang ho)) hoi. hieu va dang ((duc van) or (duc va)) hanh vi cua tre".
• Adding a wildcard symbol may retrieve word variants: su sach y ((nang o) OR (nang ho)) hoi. hieu va dang ((duc van) or (duc va)) hanh vi cua tre*.