Perhaps you should try some spelling variations:
dang xay » dang van, van xay
tham cuu » cham cuu, tham cung, thai cua
van hanh » van thanh, ban hanh, van anh
su sach » so sach, vu sach
nang xa » nang x, lang xa, nang ma
hieu va » lieu va, hieu qua
va tham » van tham, va cham, va thanh
hanh ki » hanh vi, hanh ky, hanh kien
su viet » so viet
sach v » sach va, sach y, sach 2
ki su » ky su

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach v ((nang xa) or (dang xay)) hoi. hieu va tham cuu van hanh ki su viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach v ((nang xa) OR (dang xay)) hoi. hieu va tham cuu van hanh ki su viet.
• Adding a wildcard symbol may retrieve word variants: su sach v ((nang xa) or (dang xay)) hoi. hieu va tham cuu van hanh ki su viet*.