Perhaps you should try some spelling variations:
van thanh » ban thanh, van tuan
thu sach » tu sach, thuat sach, thuoc sach
ky lang » ky dang, ky tang, tay lang
hieu ve » hieu va, hieu van
cac lop » cac hop, cac loai
van anh » tuan anh, van minh
cua tre » cua te, cuu tre, cua triet
ve cac » va cac, vien cac
va cua » va chua, via cua, ca cua

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