Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
nang xa » lang xa, nang ma, mang xa
van cau » van dau, van hau, van chat
truc va » thuc va, thuc vat, trung va
va tinh » may tinh
tinh do » trinh do, tinh doi, tinh da
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 cau truc va tinh 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 cau truc va tinh do cua tre.
• Adding a wildcard symbol may retrieve word variants: su sach ky ((nang xa) or (nang x)) hoi. hieu van cau truc va tinh do cua tre*.