Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
cac nuoc » cap nuoc, hoc nuoc, dat nuoc
sach ty » sach y, sach tu, sach thu
vu sach » vu bach, su sach, vu khach
hieu ve » hieu va
nang xa » nang x, lang xa, nang ma
ty nang » ky nang, ty xang, ty hang
va dan » ca dan, va dao, va dau
dan vi » doan vi, don vi, dan va
cua tu » cua tuc, cua su, cua cu

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

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