Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
tu sach » thu sach, su sach, te sach
sach ty » sach y, sach tu, sach thu
nang xa » lang xa, nang ma, mang xa
hieu ve » hieu va, hieu van
cam luc » cam xuc, cau luc
luc van » luoc van, luu van, duc van
ve cam » ve cham, ve cac, va cam
vi su » va su, ve su, ki su
kien » bien, vien, tien

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 ty ((nang xa) or (nang x)) hoi. hieu ve cam luc van hanh vi su kien~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty ((nang xa) OR (nang x)) hoi. hieu ve cam luc van hanh vi su kien.
• Adding a wildcard symbol may retrieve word variants: tu sach ty ((nang xa) or (nang x)) hoi. hieu ve cam luc van hanh vi su kien*.