Perhaps you should try some spelling variations:
ve triet » va trien, su triet
van hanh » van thanh, ban hanh, van anh
vien cac » vien bach, vien dai, gian cac
sang ma » tang ma, sang tao, mang may
sach ky » sac ky, sach y, sach ty
vien da » vien dai, hien dai
toc van » hoc van, toc san, tac van
nang ma » tang ma, nang cao, mang may
vu sach » vu bach, su sach, vu khach
vi ve » va ve, gi ve, ve ve

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 ky ((nang ma) OR (sang ma)) hoi. hieu ((vien cac) or (vien da)) toc van hanh vi ve triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu sach ky ((nang ma) OR (sang ma)) hoi. hieu ((vien cac) OR (vien da)) toc van hanh vi ve triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "vu sach ky ((nang ma) OR (sang ma)) hoi. hieu ((vien cac) or (vien da)) toc van hanh vi ve triet".
• Adding a wildcard symbol may retrieve word variants: vu sach ky ((nang ma) OR (sang ma)) hoi. hieu ((vien cac) or (vien da)) toc van hanh vi ve triet*.