Perhaps you should try some spelling variations:
hieu viec » nhieu viec, hieu ve, sieu viet
viec cac » vien cac, viec cua, viec lam
tu sach » thu sach, te sach, tu cach
hai cua » thai cua, dai cua, hoi cua
va lang » va nang, hoa lang
va lanh » va danh, va hanh, va anh
cac lao » ca lao, cac loai, cac giao
nang xa » nang x, lang xa, nang ma
su sach » so sach, vu sach
cua tre » cua te, cuu tre, cua triet

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 (su sach)) ky nang xa hoi. hieu viec cac lao ((va lanh) OR (va lang)) hai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (su sach)) ky nang xa hoi. hieu viec cac lao ((va lanh) OR (va lang)) hai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (su sach)) ky nang xa hoi. hieu viec cac lao ((va lanh) OR (va lang)) hai cua tre".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (su sach)) ky nang xa hoi. hieu viec cac lao ((va lanh) OR (va lang)) hai cua tre*.