Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
nang xa » lang xa, nang ma, mang xa
thuc va » thuc dan, thuc day
tinh va » tich va, trinh van, trinh vat
cuu tre » cua tre, cau tren, cau treo
va cuu » va cau, va chu, va huu

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach ky ((nang xa) or (nang x)) hoi. hieu van nam ((thuc va) OR (thuc vat)) tinh va cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky ((nang xa) OR (nang x)) hoi. hieu van nam ((thuc va) OR (thuc vat)) tinh va cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky ((nang xa) or (nang x)) hoi. hieu van nam ((thuc va) OR (thuc vat)) tinh va cuu tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ky ((nang xa) or (nang x)) hoi. hieu van nam ((thuc va) OR (thuc vat)) tinh va cuu tre*.