Perhaps you should try some spelling variations:
sach van » sach han, sach va, bach van
sang tao » hang tai
luc van » luoc van, luu van, duc van
xuc van » duc van, xuc ban, thuc van
hieu ve » hieu va, hieu van
su sach » so sach, vu sach
sang ma » tang ma, nang ma, mang may
su tien » su kien, su hien, tu tieng
ve cam » ve cham, ve cac, va cam
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 van ((sang ma) OR (sang tao)) hoi. hieu ve cam ((xuc van) or (luc van)) hanh vi su tien~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach van ((sang ma) OR (sang tao)) hoi. hieu ve cam ((xuc van) OR (luc van)) hanh vi su tien.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach van ((sang ma) OR (sang tao)) hoi. hieu ve cam ((xuc van) or (luc van)) hanh vi su tien".
• Adding a wildcard symbol may retrieve word variants: su sach van ((sang ma) OR (sang tao)) hoi. hieu ve cam ((xuc van) or (luc van)) hanh vi su tien*.