Perhaps you should try some spelling variations:
thanh di » thanh doi, thanh de, thanh do
hieu van » hieu va, thien van, lieu va
su sach » so sach, vu sach
thuc va » thuc vat, thuc dan, thuc day
van cam » van nam, van lam, van cau
cua tre » cua te, cuu tre, cua triet
ha hoi » hoa hoi, ha noi, xa hoi
y dang » ky dang, _ dang, b dang
xuc va » duc va, tuc va, luc va
2 dang » 2 danh, _ dang, b dang
di cua » dai cua, doi 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 ((y dang) OR (2 dang)) ha hoi. hieu van cam ((xuc va) or (thuc va)) thanh di cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ((y dang) OR (2 dang)) ha hoi. hieu van cam ((xuc va) OR (thuc va)) thanh di cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ((y dang) OR (2 dang)) ha hoi. hieu van cam ((xuc va) or (thuc va)) thanh di cua tre".
• Adding a wildcard symbol may retrieve word variants: su sach ((y dang) OR (2 dang)) ha hoi. hieu van cam ((xuc va) or (thuc va)) thanh di cua tre*.