Perhaps you should try some spelling variations:
hieu van » thien van, lieu va, hieu ve
cac nuoc » cap nuoc, hoc nuoc, dat nuoc
tu sach » thu sach, su sach, te sach
sach ty » sach y, sach tu, sach thu
ty nang » ky nang, ty xang, ty hang
nang xa » nang x, lang xa, nang ma
hieu va » lieu va, hieu qua
va tinh » may tinh
vi cua » vai cua, di cua
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 ty nang xa hoi. ((hieu van) OR (hieu va)) cac nuoc ((va tinh) or (lap trinh)) vi cua su~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty nang xa hoi. ((hieu van) OR (hieu va)) cac nuoc ((va tinh) OR (lap trinh)) vi cua su.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ty nang xa hoi. ((hieu van) OR (hieu va)) cac nuoc ((va tinh) or (lap trinh)) vi cua su".
• Adding a wildcard symbol may retrieve word variants: tu sach ty nang xa hoi. ((hieu van) OR (hieu va)) cac nuoc ((va tinh) or (lap trinh)) vi cua su*.