Perhaps you should try some spelling variations:
va thanh » gia thanh, ban thanh, va tinh
va khanh » van khanh, vu khanh, va hanh
hieu van » hieu va, thien van, lieu va
so sach » so sanh, bo sach, co sach
hoa cua » hoa chat, hoa xuat
cua tre » cua te, cuu tre, cua triet
nang xa » nang x, lang xa, mang xa
nang ma » tang ma, sang ma, nang cao
van am » van nam, van lam, van dam

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

• Performing a fuzzy search may retrieve terms with similar spellings: so sach y ((nang xa) or (nang ma)) hoi. hieu van am thuc ((va khanh) OR (va thanh)) hoa cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach y ((nang xa) OR (nang ma)) hoi. hieu van am thuc ((va khanh) OR (va thanh)) hoa cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach y ((nang xa) or (nang ma)) hoi. hieu van am thuc ((va khanh) OR (va thanh)) hoa cua tre*".