Perhaps you should try some spelling variations:
hanh dinh » thanh dinh, hinh dinh, hanh tinh
hieu van » hieu va, thien van, lieu va
dinh cuu » dinh chi
truc va » thuc va, trung va
van cam » van nam, van lam, van cau
cuu tre » cua tre, cau tren, cau treo
sach ty » sach tu, sach thu, xach tay
xang o » lang o, tang o, dang o
o hai » co hai, so hai, o lai

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 ty) OR (sach y)) xang o hai. hieu van cam ((truc va) or (thuc vat)) hanh dinh cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach ty) OR (sach y)) xang o hai. hieu van cam ((truc va) OR (thuc vat)) hanh dinh cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sach ty) OR (sach y)) xang o hai. hieu van cam ((truc va) or (thuc vat)) hanh dinh cuu tre".
• Adding a wildcard symbol may retrieve word variants: tu ((sach ty) OR (sach y)) xang o hai. hieu van cam ((truc va) or (thuc vat)) hanh dinh cuu tre*.