Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, hieu ve
va thanh » gia thanh, ban thanh, va tinh
thanh do » thanh de, thanh pho, thanh hoa
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
nang xa » lang xa, nang ma, mang xa
truc va » thuc va, thuc vat, trung va
cua tre » cua te, cuu tre, cua triet
do cua » doi cua, co cua, de 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 ky ((nang xa) or (nang x)) hoi. ((hieu van) OR (lieu va)) cau truc va thanh do cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky ((nang xa) OR (nang x)) hoi. ((hieu van) OR (lieu va)) cau truc va thanh do cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky ((nang xa) or (nang x)) hoi. ((hieu van) OR (lieu va)) cau truc va thanh do cua tre".
• Adding a wildcard symbol may retrieve word variants: su sach ky ((nang xa) or (nang x)) hoi. ((hieu van) OR (lieu va)) cau truc va thanh do cua tre*.