Perhaps you should try some spelling variations:
sieu viet » su viet, dien viet, bien viet
hieu viec » nhieu viec, hieu ve, hieu hien
thu sach » thuat sach, thuoc sach, thu hoach
tu sach » su sach, te sach, tu cach
cac tuc » cac toc, cac tu, cac tac
hang di » hang doi, hang vi, hang dien
nang xa » nang x, lang xa, nang ma
va hang » van hang, va nang, va lang
di cua » dai cua, doi cua, de cua
tuc va » thuc va, truc va, tuc xa
y nang » ky nang, ly nang, v nang
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) OR (thu sach)) y nang xa hoi. ((hieu viec) or (sieu viet)) cac tuc va hang di cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (thu sach)) y nang xa hoi. ((hieu viec) OR (sieu viet)) cac tuc va hang di cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) OR (thu sach)) y nang xa hoi. ((hieu viec) or (sieu viet)) cac tuc va hang di cua te".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) OR (thu sach)) y nang xa hoi. ((hieu viec) or (sieu viet)) cac tuc va hang di cua te*.