Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
so sach » so sanh, bo sach, co sach
thuc va » thuc vat, thuc dan, thuc day
doi cua » dai cua, hoi cua
van cam » van nam, van lam, van cau
di cua » dai cua, de cua, do cua
y nang » ky nang, ly nang, v nang
tuc va » truc va, tuc xa, duc va
nang o » nang co, nang ho, nang ro
o hoi » co hoi, o hoc, o hai

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 o hoi. hieu van cam ((tuc va) or (thuc va)) thanh ((di cua) OR (doi cua)) te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach y nang o hoi. hieu van cam ((tuc va) OR (thuc va)) thanh ((di cua) OR (doi cua)) te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach y nang o hoi. hieu van cam ((tuc va) or (thuc va)) thanh ((di cua) OR (doi cua)) te".
• Adding a wildcard symbol may retrieve word variants: so sach y nang o hoi. hieu van cam ((tuc va) or (thuc va)) thanh ((di cua) OR (doi cua)) te*.