Perhaps you should try some spelling variations:
cau viet » ca viet, chu viet, cao viet
thanh di » thanh doi, thanh de, thanh do
hieu va » lieu va, hieu qua
sach ly » sach lo, sach ty, sach hay
truc va » thuc vat, trung va
thuc va » thuc vat, thuc dan, thuc day
va dau » va dao
di cau » da cau, diem cau
x hoi » xa hoi, o hoi, x ho

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

• Performing a fuzzy search may retrieve terms with similar spellings: te ((sach ly) or (sach y)) nang x hoi. hieu va dau ((truc va) OR (thuc va)) thanh di cau viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te ((sach ly) OR (sach y)) nang x hoi. hieu va dau ((truc va) OR (thuc va)) thanh di cau viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te ((sach ly) or (sach y)) nang x hoi. hieu va dau ((truc va) OR (thuc va)) thanh di cau viet".
• Adding a wildcard symbol may retrieve word variants: te ((sach ly) or (sach y)) nang x hoi. hieu va dau ((truc va) OR (thuc va)) thanh di cau viet*.