Perhaps you should try some spelling variations:
danh dien » dinh dien, danh kien, danh lien
thu sach » tu sach, thuat sach, thuoc sach
hieu van » hieu va, thien van, lieu va
ky lang » ky dang, ky tang, tay lang
van cau » van dau, van hau, van chat
cau hoc » cau hoi, cau hoa, cao hoc
danh di » danh du, xanh di, danh gia
cuu tre » cua tre, cau tren, cau treo

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: thu sach ((ky lang) OR (ky nang)) xa hoi. hieu van cau hoc va ((danh di) or (danh dien)) cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ((ky lang) OR (ky nang)) xa hoi. hieu van cau hoc va ((danh di) OR (danh dien)) cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ((ky lang) OR (ky nang)) xa hoi. hieu van cau hoc va ((danh di) or (danh dien)) cuu tre".
• Adding a wildcard symbol may retrieve word variants: thu sach ((ky lang) OR (ky nang)) xa hoi. hieu van cau hoc va ((danh di) or (danh dien)) cuu tre*.