Perhaps you should try some spelling variations:
hieu viec » nhieu viec, sieu viet, hieu hien
sach nuoc » sach duoc, cac nuoc, bach tuoc
danh doi » danh di, thanh doi, dung doi
su sach » so sach, vu sach
ky lang » ky dang, ky tang, tay lang
hieu ve » hieu va, hieu van
va danh » va dinh, va dan, va hanh
doi cua » dai cua, hoi cua
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: su sach ((ky lang) OR (ky nang)) xa hoi. ((hieu viec) or (hieu ve)) sach nuoc va danh doi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ((ky lang) OR (ky nang)) xa hoi. ((hieu viec) OR (hieu ve)) sach nuoc va danh doi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ((ky lang) OR (ky nang)) xa hoi. ((hieu viec) or (hieu ve)) sach nuoc va danh doi cua tre".
• Adding a wildcard symbol may retrieve word variants: su sach ((ky lang) OR (ky nang)) xa hoi. ((hieu viec) or (hieu ve)) sach nuoc va danh doi cua tre*.