Perhaps you should try some spelling variations:
van dung » van dong, xay dung, tin dung
van hanh » van thanh, ban hanh, van anh
su sach » so sach, vu sach
hieu ve » hieu va, hieu van
cam duc » cam xuc, cao duc, pham duc
duc van » duc va, duc tan, duc manh
ve cam » ve cham, ve cac, va cam
vi su » va su, ve su, oi su
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: su sach ((van dung) or (van ban)) xa hoi. hieu ve cam duc van hanh ((vi su) OR (ki su)) triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ((van dung) OR (van ban)) xa hoi. hieu ve cam duc van hanh ((vi su) OR (ki su)) triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ((van dung) or (van ban)) xa hoi. hieu ve cam duc van hanh ((vi su) OR (ki su)) triet".
• Adding a wildcard symbol may retrieve word variants: su sach ((van dung) or (van ban)) xa hoi. hieu ve cam duc van hanh ((vi su) OR (ki su)) triet*.