Perhaps you should try some spelling variations:
sach thi » sach thu, sach tai, sach thieu
thi nang » thi cong, ki nang, thi hanh
nang cau » nang cao, hang cau, nang dau
nam thuc » nam thuoc, am thuc, nam thu
van hanh » van thanh, ban hanh, van anh
hanh tai » thanh tai, hang tai, han tai
su triet » su viet, su tien, ve triet
tu sach » thu sach, su sach, te sach
hieu va » lieu va, hieu qua
cam tuc » cam xuc, cam tu, dam thuc
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 nang cau hoi. hieu va ((cam tuc) OR (nam thuc)) van hanh tai su triet~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach thi nang cau hoi. hieu va ((cam tuc) OR (nam thuc)) van hanh tai su triet".
• Adding a wildcard symbol may retrieve word variants: tu sach thi nang cau hoi. hieu va ((cam tuc) OR (nam thuc)) van hanh tai su triet*.