Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
thi hang » thi hanh, thi nang, thi hong
hieu cac » hieu luc, hieu va, hieu van
cac nhat » cac nha, cac nhan, cac chat
nhat tai » nhan tai, chat tai, nha tai
vanh dai » van dai, vanh tai, lanh dao
su triet » su viet, su tien, ve triet
va vanh » va van, va hanh, va danh
tai va » thai va, mai va, tri va
dai su » dai sua, dai so, dan su

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 ((thuc hanh) or (thi hang)) cau hoi. hieu cac nhat tai va vanh dai su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ((thuc hanh) OR (thi hang)) cau hoi. hieu cac nhat tai va vanh dai su triet.
• Adding a wildcard symbol may retrieve word variants: thu sach ((thuc hanh) or (thi hang)) cau hoi. hieu cac nhat tai va vanh dai su triet*.