Perhaps you should try some spelling variations:
su triet » su viet, su tien, ve triet
hanh vai » hanh vi, hanh va, hanh tai
van hanh » van thanh, ban hanh, van anh
thuc van » thuc vat, thuc dan, thuc va
sach ky » sac ky, sach y, sach ty
tu sach » thu sach, su sach, te sach
ky dang » ky nang, ky danh
le nam » ly nam, he nam, le na
ha hoi » hoa hoi, xa hoi, va hoi
vai su » va su, van su, lai su
ve nam » he nam, va nam, te nam

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 ky dang ((ha hoi) or (ha noi)). hieu ((ve nam) or (le nam)) thuc van hanh vai su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky dang ((ha hoi) OR (ha noi)). hieu ((ve nam) OR (le nam)) thuc van hanh vai su triet.
• Adding a wildcard symbol may retrieve word variants: tu sach ky dang ((ha hoi) or (ha noi)). hieu ((ve nam) or (le nam)) thuc van hanh vai su triet*.