Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
van hanh » van thanh, ban hanh, van anh
sach ty » sach y, sach tu, sach thu
xuc van » duc van, luc van, vuc van
vu cham » va cham, vu kham, tu cham
ve cham » va cham, ve chat, ve chim
tang ma » mang may, tang van
ty tang » tay tang, ty xang, ty hang
vai va » mai va, dai va, lai va
hai va » hai van, thai va, hoi va
thiet » thieu

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

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