Perhaps you should try some spelling variations:
thien van » thi van
ban thanh » ban hanh, ban hang
thanh vi » hanh vi, thanh va, thanh ve
quoc ban » quoc bao, quoc lan, quoc quan
lam quoc » lam duoc, nam quoc, lam thuoc
hieu van » hieu va, lieu va, hieu ve
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
nang ma » tang ma, sang ma, mang may
cuu tre » cua tre, cau tren, cau treo
vi cuu » vi luu, vinh cuu

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