Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
hanh tai » thanh tai, hang tai, han tai
thuc va » thuc dan, thuc day
su hien » su kien, su tien, thu hien
hieu ve » hieu va, hieu van
lang xa » lang ha, dang xay, lang van
nang xa » nang x, nang ma, mang xa
tai su » tai so, tai tu, lai su
ve cam » ve cham, ve cac, va cam

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

• Performing a fuzzy search may retrieve terms with similar spellings: thu sach y ((nang xa) or (lang xa)) hoi. hieu ve cam ((thuc va) OR (thuc vat)) hanh tai su hien~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach y ((nang xa) OR (lang xa)) hoi. hieu ve cam ((thuc va) OR (thuc vat)) hanh tai su hien.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach y ((nang xa) or (lang xa)) hoi. hieu ve cam ((thuc va) OR (thuc vat)) hanh tai su hien".
• Adding a wildcard symbol may retrieve word variants: thu sach y ((nang xa) or (lang xa)) hoi. hieu ve cam ((thuc va) OR (thuc vat)) hanh tai su hien*.