Perhaps you should try some spelling variations:
phat triet » phat trien, chet triet, khac triet
van hanh » van thanh, ban hanh, van anh
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
nang xa » nang x, lang xa, mang xa
nang ma » tang ma, sang ma, nang cao
thi van » thi lan, thi hanh, thi nang
xuc van » duc van, luc van, vuc van
hanh va » hang va, hanh vi

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

• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky ((nang xa) OR (nang ma)) hoi. ((thien van) OR (thi van)) bac xuc van hanh va phat triet~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky ((nang xa) or (nang ma)) hoi. ((thien van) OR (thi van)) bac xuc van hanh va phat triet~".
• Adding a wildcard symbol may retrieve word variants: tu sach ky ((nang xa) or (nang ma)) hoi. ((thien van) OR (thi van)) bac xuc van hanh va phat triet*.