Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, hieu ve
cuu thuc » cuu tac
thuc dan » thuc hanh, hoc dan, thuc vat
dan hanh » dang hanh, dan khanh, dan thanh
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
nang xa » nang x, lang xa, nang ma
hanh ve » hanh vi, hanh va, hanh kem
cua te » cua tu
cua su » qua su

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach ky nang xa hoi. ((hieu van) OR (lieu va)) cuu thuc dan hanh ve ((cua te) or (cua su))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang xa hoi. ((hieu van) OR (lieu va)) cuu thuc dan hanh ve ((cua te) OR (cua su)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky nang xa hoi. ((hieu van) OR (lieu va)) cuu thuc dan hanh ve ((cua te) or (cua su))".
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang xa hoi. ((hieu van) OR (lieu va)) cuu thuc dan hanh ve ((cua te) or (cua su))*.