Perhaps you should try some spelling variations:
hieu viec » nhieu viec, hieu ve, sieu viet
van thanh » ban thanh
va triet » va thiet, va trien, ve triet
van tuan » van quan, van ban, anh tuan
viec cac » vien cac, viec cua, viec lam
cac tac » cac toc, cac bac, cac dac
ky tang » ky nang, ky dang, kho tang
ky lang » ky nang, ky dang, tay lang
su sach » so sach, vu sach
hai va » hai van, thai va, hoi va

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