Perhaps you should try some spelling variations:
thien van » thi van
nam trung » nam trong, tai trung, ba trung
hieu van » hieu va, lieu va, hieu ve
trung va » truong va, trang va, trung ha
su sach » so sach, vu sach
sach ly » sach y, sach lo, sach ty
ly nang » ky nang, ly hang, ly vang
va hanh » van hanh, va thanh, va danh
cua tre » cua te, cuu tre, cua triet
ma hoi » mai hoi, xa hoi, me hoi
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 ly nang ((ma hoi) OR (ma hoa)). ((hieu van) or (thien van)) nam trung va hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ly nang ((ma hoi) OR (ma hoa)). ((hieu van) OR (thien van)) nam trung va hanh vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ly nang ((ma hoi) OR (ma hoa)). ((hieu van) or (thien van)) nam trung va hanh vi cua tre".
• Adding a wildcard symbol may retrieve word variants: su sach ly nang ((ma hoi) OR (ma hoa)). ((hieu van) or (thien van)) nam trung va hanh vi cua tre*.