Perhaps you should try some spelling variations:
van thiet » va thiet, dan thiet, can thiet
ve cham » va cham, ve chat, vu cham
sach ky » sac ky, sach ty, sach kem
nang ma » tang ma, sang ma, nang cao
hieu ve » hieu va, hieu van
ma hoi » mai hoi, xa hoi, ma hoa
xuc va » duc va, tuc va, xac va
luc va » duc va, tuc va, loc va

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu ((sach ky) or (sach y)) nang ma hoi. hieu ve cham ((xuc va) OR (luc va)) hanh vi van thiet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach ky) OR (sach y)) nang ma hoi. hieu ve cham ((xuc va) OR (luc va)) hanh vi van thiet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sach ky) or (sach y)) nang ma hoi. hieu ve cham ((xuc va) OR (luc va)) hanh vi van thiet".
• Adding a wildcard symbol may retrieve word variants: tu ((sach ky) or (sach y)) nang ma hoi. hieu ve cham ((xuc va) OR (luc va)) hanh vi van thiet*.