Perhaps you should try some spelling variations:
cau triet » cau trieu, su triet, cua triet
van hanh » van thanh, van anh, van ban
ban hanh » ban hang
su sach » so sach, vu sach
tang xa » trang xa, tang ma, lang xa
sach 6 » sach y, sach 2
ve cam » ve cham, va cam, ve cai
ve cac » va cac, vien cac
vi cau » va cau, ve cau, di cau

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 6 tang xa hoi. hieu ((ve cam) or (ve cac)) tuc ((van hanh) or (ban hanh)) vi cau triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach 6 tang xa hoi. hieu ((ve cam) OR (ve cac)) tuc ((van hanh) OR (ban hanh)) vi cau triet.
• Adding a wildcard symbol may retrieve word variants: su sach 6 tang xa hoi. hieu ((ve cam) or (ve cac)) tuc ((van hanh) or (ban hanh)) vi cau triet*.