Perhaps you should try some spelling variations:
vao triet » va triet, mao triet, ve triet
toc sach » hoc sach, doc sach, thuoc sach
va trien » va truyen, va thiet, va tuyen
nang ma » tang ma, sang ma, nang cao
hieu va » hieu qua
va hanh » van hanh, va thanh, va danh
hanh di » hanh vi, hanh de, hang di
ma hoi » mai hoi, xa hoi, ma hoa
sach v » sach va, sach y, sach 2
xuc va » duc va, tuc va, luc va
v nang » va nang, vu nang, van nang

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

• Performing a fuzzy search may retrieve terms with similar spellings: toc sach v nang ma hoi. ((hieu va) or (lieu va)) cam xuc va hanh di ((vao triet) OR (va trien))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach v nang ma hoi. ((hieu va) OR (lieu va)) cam xuc va hanh di ((vao triet) OR (va trien)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach v nang ma hoi. ((hieu va) or (lieu va)) cam xuc va hanh di ((vao triet) OR (va trien))".
• Adding a wildcard symbol may retrieve word variants: toc sach v nang ma hoi. ((hieu va) or (lieu va)) cam xuc va hanh di ((vao triet) OR (va trien))*.