Perhaps you should try some spelling variations:
sach dao » lanh dao
van hanh » van thanh, ban hanh, van anh
hai cua » thai cua, dai cua, hoi cua
vai cua » dai cua, lai cua, bai cua
vu sach » vu bach, su sach, vu khach
hieu ve » hieu va, hieu van
nang xa » lang xa, nang ma, mang xa
cam tu » cam thu, nam tu, dam tu
tu van » tu va
ve cam » ve cham, ve cac, va cam

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

• Performing a fuzzy search may retrieve terms with similar spellings: vu sach dao ((nang xa) OR (nang x)) hoi. hieu ve cam tu van hanh ((vai cua) or (hai cua)) viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu sach dao ((nang xa) OR (nang x)) hoi. hieu ve cam tu van hanh ((vai cua) OR (hai cua)) viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "vu sach dao ((nang xa) OR (nang x)) hoi. hieu ve cam tu van hanh ((vai cua) or (hai cua)) viet".
• Adding a wildcard symbol may retrieve word variants: vu sach dao ((nang xa) OR (nang x)) hoi. hieu ve cam tu van hanh ((vai cua) or (hai cua)) viet*.