Perhaps you should try some spelling variations:
thien van » thi van
hieu van » hieu va, lieu va, hieu ve
van hanh » van thanh, ban hanh, van anh
truc van » truc va, thuc van, truc ban
cam truc » cau truc, nam truc, lam truoc
su sach » so sach, vu sach
nang ma » tang ma, sang ma, nang cao
cua tre » cua te, cuu tre, cua triet
sach v » sach va, sach y, sach 2
vi cua » vai cua, di cua

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

• If you are trying to use Boolean operators, they must be ALL CAPS: su sach v ((nang x) OR (nang ma)) hoi. ((hieu van) OR (thien van)) cam truc van hanh vi cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach v ((nang x) or (nang ma)) hoi. ((hieu van) OR (thien van)) cam truc van hanh vi cua tre~".
• Adding a wildcard symbol may retrieve word variants: su sach v ((nang x) or (nang ma)) hoi. ((hieu van) OR (thien van)) cam truc van hanh vi cua tre*.