Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
dua tren » dung tren
hieu van » hieu va, thien van, lieu va
sach ty » sach y, sach tu, sach thu
cua tre » cua te, cuu tre, cua thep
tinh ve » trinh ve, tinh ven, dinh ve
su sach » so sach, vu sach
cac duc » cac du, cao duc, cac dac
van cac » van hac, van cau, van bac
nang xa » nang x, lang xa, nang ma
ty nang » ky nang, ty xang, ty hang
va tinh » may tinh

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach ty nang xa hoi. hieu van cac duc va tinh ve ((((cua tre) OR (dua tren))) or (cua triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ty nang xa hoi. hieu van cac duc va tinh ve ((((cua tre) OR (dua tren))) OR (cua triet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ty nang xa hoi. hieu van cac duc va tinh ve ((((cua tre) OR (dua tren))) or (cua triet))".
• Adding a wildcard symbol may retrieve word variants: su sach ty nang xa hoi. hieu van cac duc va tinh ve ((((cua tre) OR (dua tren))) or (cua triet))*.