Perhaps you should try some spelling variations:
hieu viec » nhieu viec, hieu ve, sieu viet
viec day » viec dat, viec xay, viec hay
thuc van » thuc dan, thuc va, thuc hanh
dieu cua » dieu tra
su sach » so sach, vu 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
de cua » le cua, te cua

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