Perhaps you should try some spelling variations:
thinh duc » tinh duc, trinh duc, trinh duoc
hieu van » hieu va, thien van, hieu ve
su sach » vu sach
so sach » so sanh, bo sach, co sach
vu nang » vuc nang, va nang, vu dang
cao hoc » co hoc, cho hoc, chat hoc
va hanh » van hanh, va thanh, va danh
cua tre » cua te, cuu tre, cua triet
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) OR (so sach)) vu nang cao hoc. ((hieu van) or (lieu va)) thinh duc va hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sach) OR (so sach)) vu nang cao hoc. ((hieu van) OR (lieu va)) thinh duc va hanh vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((su sach) OR (so sach)) vu nang cao hoc. ((hieu van) or (lieu va)) thinh duc va hanh vi cua tre".
• Adding a wildcard symbol may retrieve word variants: ((su sach) OR (so sach)) vu nang cao hoc. ((hieu van) or (lieu va)) thinh duc va hanh vi cua tre*.