Perhaps you should try some spelling variations:
su triet » su viet, su tien, ve triet
vien cac » vien bach, vien dai, vien da
sach tu » sach thu, cach tu, sach ty
duc ban » duc tan, duc van, dua ban
qua ban » cua ban, qua quan
tu nang » tru nang, tu nong, tu nano
hanh ki » hanh vi, hanh ky, hanh kien
tu sach » thu sach, su sach, te sach
ve cac » va cac
x hoi » xa hoi, o hoi, x ho
ki su » ky 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 tu nang x hoi. hieu ((ve cac) OR (vien cac)) ((duc ban) or (qua ban)) hanh ki su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach tu nang x hoi. hieu ((ve cac) OR (vien cac)) ((duc ban) OR (qua ban)) hanh ki su triet*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach tu nang x hoi. hieu ((ve cac) OR (vien cac)) ((duc ban) or (qua ban)) hanh ki su triet*".