Perhaps you should try some spelling variations:
su triet » su viet, su tien, ve triet
sach kha » sach nha, sach ha, sach tham
van hanh » van thanh, ban hanh, van anh
nam thuc » nam thuoc, am thuc, nam thu
cam thuc » am thuc, cam thu, can thuc
su sach » so sach, vu sach
nang xa » lang xa, nang ma, mang xa
hieu ve » hieu va, hieu van
vi su » va su, ve su, ki su

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

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