Perhaps you should try some spelling variations:
hanh cua » manh cua, hang cua, hanh sua
van hanh » van thanh, ban hanh, van anh
hieu van » hieu va, thien van, lieu va
so sach » so sanh, bo sach, co sach
luc van » luoc van, luu van, duc van
cam luc » cam xuc, cau luc
hieu ve » hieu va
sach ky » sac ky, sach y, sach ty
nang ma » tang ma, sang ma, nang cao
lang xa » lang ha, dang xay, lang van
cua va » cua vat, chua va, cua van
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: so sach ky ((lang xa) or (nang ma)) hoi. ((hieu ve) OR (hieu van)) cam luc van hanh cua va thiet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach ky ((lang xa) OR (nang ma)) hoi. ((hieu ve) OR (hieu van)) cam luc van hanh cua va thiet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach ky ((lang xa) or (nang ma)) hoi. ((hieu ve) OR (hieu van)) cam luc van hanh cua va thiet".
• Adding a wildcard symbol may retrieve word variants: so sach ky ((lang xa) or (nang ma)) hoi. ((hieu ve) OR (hieu van)) cam luc van hanh cua va thiet*.