Perhaps you should try some spelling variations:
thien van » thi van
van hanh » van thanh, ban hanh, van anh
dang xay » dang van, van xay
tu sach » thu sach, su sach, te sach
hanh va » hang va, hanh vi
tuc van » thuc van, truc van, tuc va
hac tuc » thac toc, thai tuc
su viet » so viet
sach ky » sac ky, sach y, sach ty
hieu va » lieu va, hieu qua
nang xa » nang x, lang xa, nang ma

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 ky ((nang xa) or (dang xay)) hoi. ((hieu va) or (thien van)) hac tuc van hanh va su viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky ((nang xa) OR (dang xay)) hoi. ((hieu va) OR (thien van)) hac tuc van hanh va su viet.
• Adding a wildcard symbol may retrieve word variants: tu sach ky ((nang xa) or (dang xay)) hoi. ((hieu va) or (thien van)) hac tuc van hanh va su viet*.