Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
van hanh » van thanh, ban hanh, van anh
va hanh » va thanh, va danh, ban hanh
cua tre » cua te, cuu tre, dua tren
te sach » toc sach
cam loc » cam lo
hieu va » lieu va, hieu qua
nang xa » nang x, lang xa, nang ma
sach v » sach va, sach y, sach 2
va cam » va cham, va cac, va cao
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: te sach v nang xa hoi. hieu va cam loc ((va hanh) OR (van hanh)) lam ((cua tre) or (cua triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach v nang xa hoi. hieu va cam loc ((va hanh) OR (van hanh)) lam ((cua tre) OR (cua triet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach v nang xa hoi. hieu va cam loc ((va hanh) OR (van hanh)) lam ((cua tre) or (cua triet))".
• Adding a wildcard symbol may retrieve word variants: te sach v nang xa hoi. hieu va cam loc ((va hanh) OR (van hanh)) lam ((cua tre) or (cua triet))*.