Perhaps you should try some spelling variations:
sach thi » sach thu, sach tai, sach thieu
thi hanh » thi thanh
hanh cau » nhanh cau, hang cau, hanh cac
truc van » thuc van, truc ban, truc dan
hanh tai » thanh tai, hang tai, han tai
su triet » su viet, su tien, ve triet
tu sach » thu sach, su sach, te sach
qua cam » qua cham, qua cac, qua ca
truc va » thuc va, thuc vat, trung va
tai su » tai so, tai tu, lai su

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 thi hanh cau hoi. hieu qua cam ((truc van) or (truc va)) hanh tai su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach thi hanh cau hoi. hieu qua cam ((truc van) OR (truc va)) hanh tai su triet.
• Adding a wildcard symbol may retrieve word variants: tu sach thi hanh cau hoi. hieu qua cam ((truc van) or (truc va)) hanh tai su triet*.