Perhaps you should try some spelling variations:
hieu quan » hieu qua, lieu quan, thien quan
danh vien » doanh vien, dan vien, danh kien
danh viet » anh viet, ninh viet, nang viet
quan cau » quang cao, toan cau, quan ha
tu sach » thu sach, su sach, te sach
ky lang » ky nang, ky dang, tay lang
ky tang » ky nang, ky dang, kho tang
truc va » thuc va, thuc vat, trung va

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 ((ky lang) OR (ky tang)) xa hoi. hieu quan cau truc va ((danh vien) or (danh viet)) cac tro~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((ky lang) OR (ky tang)) xa hoi. hieu quan cau truc va ((danh vien) OR (danh viet)) cac tro.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((ky lang) OR (ky tang)) xa hoi. hieu quan cau truc va ((danh vien) or (danh viet)) cac tro".
• Adding a wildcard symbol may retrieve word variants: tu sach ((ky lang) OR (ky tang)) xa hoi. hieu quan cau truc va ((danh vien) or (danh viet)) cac tro*.