Perhaps you should try some spelling variations:
vat hanh » vat thanh, van hanh, va hanh
hieu van » thien van, lieu va, hieu ve
hanh tue » hanh tu, hanh tuyen, hanh theo
tu sach » thu sach, su sach, te sach
ty nang » ky nang, ty xang, ty hang
nang xa » nang x, lang xa, nang ma
tue cua » te cua
hieu va » lieu va, hieu qua
sach ty » sach y, sach tu, sach thu
cuu tac » cuu dac, cuu cac, cuu xac
cua te » cua tu

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 ty nang xa hoi. ((hieu van) OR (hieu va)) ((cuu thuc) or (cuu tac)) vat hanh tue cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty nang xa hoi. ((hieu van) OR (hieu va)) ((cuu thuc) OR (cuu tac)) vat hanh tue cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ty nang xa hoi. ((hieu van) OR (hieu va)) ((cuu thuc) or (cuu tac)) vat hanh tue cua te".
• Adding a wildcard symbol may retrieve word variants: tu sach ty nang xa hoi. ((hieu van) OR (hieu va)) ((cuu thuc) or (cuu tac)) vat hanh tue cua te*.