Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
duc van » duc va, duc tan, duc manh
lang xa » lang ha, dang xay, lang van
ky lang » ky nang, ky dang, ky tang
ve cai » va cai, ve tai, ve cau
ve cac » va cac, vien cac
vi su » ve su, ki su, oi 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 ky lang xa hoi. hieu ((ve cai) or (ve cac)) duc van hanh ((vi su) OR (va su)) viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky lang xa hoi. hieu ((ve cai) OR (ve cac)) duc van hanh ((vi su) OR (va su)) viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky lang xa hoi. hieu ((ve cai) or (ve cac)) duc van hanh ((vi su) OR (va su)) viet".
• Adding a wildcard symbol may retrieve word variants: su sach ky lang xa hoi. hieu ((ve cai) or (ve cac)) duc van hanh ((vi su) OR (va su)) viet*.